The items are a big reason why minion Generals just don't work.
  The cost effectiveness of buying idols, and then buying items that buff your minions, does not add up.  The same general spending no money on idols, and just buying items to buff the General will Do better.  The issue can be fixed best with improvements to the items, with not really needing to adjust the idols stats(though Siege Archers do need about 50%-100% more damage vs. players..  They do decent damage against buildings), or their price(though idols do need a 1k price drop for level4's across the board.  And frankly, I don't see the point in level 2 and level 3 idols.  I'd only ever buy the level 1 or level 4 I'm sure.)

  I'm not saying that no general minion build is good.  There are some that are.  Generals are not bad.  But in every decent general minion build I've seen, and played myself, the minion buffing items are not used.   They are simply not worth the gold.

  Shamblers are alright, especially with Mulch.  Yeti's are quite good too, though I do prefer non-minion Sedna more.  Oak's are nice.  Night Walkers are.. well alright I guess(though IMO could use a 5%-8% buff to movement speed).
  Consider that you spend 7.5k getting the lvl4 Priests, lvl4 archers, and then another 4.5k on, say, the armor that gives you some health and armor, and gives your minions some health.  That's 12k.  For 10k-12k you can get a great item from the artifact shop which we know is WAY better.  I won't even mention the minotaurs..

  I would rarely get anything beyond the 1k priests at this point.  They are great at the start for longetivity in the middle, not needing to return to crystal.  I get those 1k priests, then all I spend on items is the buff my demigod.

  If your demigod dies, your minions die, so you want your demigod to live.  You can make more minions while alive, which is what makes most of the items bad.  Alot of it comes down to "cost per performance".  Minions items have bad "cost per performance" because you're already spending money on priests or archers in the first place.  And even if you don't, they simply aren't worth it compared to non-minion buffing items to just buff your skill minions.
  And.. something needs to be done about this, IMO.

Also, I don't think the math that came to make the attack speed buff is very good.

Take Gloves of FellDarkur for example.  Lets say, just to make the math clean, that you have, oh.. 10 Night Walkers, that attack once per second, doing 20 damage per attack.  Not sure what actual numbers are for Night Walkers, though, honestly.:

Even if you used yeti's as an example, it makes no sense why you would bother with 5% attack speed.  +damage is multiplicative with minions, while attack speed is simply additive.  In most cases, it seems that +2 or +3 damage is going to do more than +5% attack speed.  Heck.. it's like the +5% attack speed is simply there to look pretty, rather than do anything useful.  It's such a tiny difference that only spreadsheets would notice it when looking at past the decimal points.
That +5% should be more like +20%, and the item at least 1k cheaper!

Then, there comes the fun in it.  What fun is it to give my minions 30% more(about what +300 does) health, a little more armor?  It is barely noticable compared to giving my Demigod that, or giving my demigod an ability, an activated item.  What use is healing my minions 33% really going to do?
Items need to do things more like.. Maybe I'd pay 2.5k for something that was making my priests heal twice as often, or another item that gave them a chain heal which healed 3 targets at once, and they healed themselves every time they healed allies.  And then, I'd maybe I'd pay the 4k for those high level priests in the first place.
Or an item that gives more range and ranged damage, so it'd just effect shamblers and siege archers.  That'd be something that'd favor QoT getting siege archers, since it'd benefit shamblers aswell, but maybe not as much the others.  But that adds more variance.
Right now the minion items are BLANDDD.

So.. some suggestions I've give:

Forest Band $1250
   Currently, why would you buy this over Wand of Speed?  Wand of Speed is pretty dang good.  Forest band is pretty dang useless.
   First of all:  IF a minion dies, you summon anothr.  You die, your enemy gains a lot of gold, you have to wait in limbo, and you have to resummon ALL your minions.

   Take, for example, life leach.  Every hit, someone is gaining a good chunk of health.  In fact, I think life leach is rather overpowered.  At higher levels some builds can pretty much tank indefinitely with it.
This would be similar, but you can focus on healing yourself via your minions, rather than needing high damage and life leach to accomplish it.
   If you have 500 damage and 15% life leach, that is 75 health gained per hit.  In this case, if you have 12 minions that you're healing, you are averaging 120 health healed on hit.  Though, only Dr. Acula and Oak can get that many minions.  Sedna or QoT could get 10 (4+2+2+2) by buying all the minions and investing in the skills.  Also, keep in mind that those good life leach items and such are going to be giving someone more attack speed, generally, so the heal per seconds would be closer.

Another interesting attribute of this is that it'd add some progression to the item.  At the start, you can't have as many minions, so the health gained is minor.  You'd only average 120 gained on hit towards the late game if you had 10 nightwalkers and priests to give you 12 minions.
And yet another interesting attribute, is that it makes it effective to kill minions first on someone doing this, since they lose their heal.

Twig of Life $3000
   It's just.. Not useful.  It needs to be scraped and replaced with something better.

While 50% reduced cooldown on priests heal would SEEM like a lot for 3k.. keep in mind you'd need to spend the 4k on Level4 priests to get the best benefit out of it in the first place, so that's 7k!  So it should be more considered as a 7k item.

Commanders Crown (new suggested item, or replace something else) $7500
Something new i'd suggest to go under helms, as there is plenty of room there for more items.

While the first is seemingly powerful, it requires AT LEAST 1 of EACH of the Priests, Minotaurs, and archers to be alive, not either of the 3.
Also, the minimum cost to get the 1st benefit would be 500+750+1000+7500 gold.   On the other benefits, you at least need 2 different minions.  You gain no benefit at all from the item and just 1 set of minions.  Also, the benefits are lower with the cheaper minions since the cheaper minions die easier, so you more easily knocked out simply by aoe to negate the first benefit, and archers gain less benefit from double damage, etc.  So consider what else you could get from spending 10k-20k

Hauberk of Life $1750
  Even as a general, I'd take the $1500 armor that gives better stats to my general over this EVERY time.

   An added benefit would be that not only are they leaching life, healing themselves, and thus healing you, but your priests healing themselves or your minions will also heal you. Eredus's giving them leach(which I think is a stupid skill..) will increase the heal, Sedna healing one of her minions(does anyone bother doing that? ) would heal you.
   However, without +health per second skills or items, you'll lose health out of battle.

Ring of the Ancients => Ring of the Overseer $3500
+30 damage and +400 armor is pretty redundant.  Sure there isn't an item that gives damage AND armor in the main shop, but it's not worth it, and even with better stats i'd still just buy gloves and an armor seperately to get nice +life and +armor, and +dmg seperately for half the price.
So replace it with..

With this you can buff the creepwaves nicely, and your other minions so-so, and other demigods minorly that are in the area.  The benefit is considerable if you have all 3 idols of max level (+18 damage, +120 life, +120armor, 8MPS).  Wouldn't hurt to make the armor and life percentange instead though.. Like 2% per idol level.

Generic suggestions about items
Other things I'd like to see added to some of the current items is like.. Say Cloak of Einfield.  How about +1% additional evasion rate for each minion(cap at +10% additional)?  And other things like that on some other items.

I'd also like to see an item that is +50 damage to minions and +15% attack speed, that isn't very expensive.  But it has -3 damage per minion.  So it's more effective for Sedna and QoT's minions than the Oak and Dr. Acula.

The game needs more items with stats and such like that, not just simple +life, +damage, +armor..

More activated are good too.

And then you have the General's Minion skills
Namely I have a BIG issue with the "Morale" skill.
All the Generals(except Oak?) already have a skill that buffs their minions.  It's not as if I'm going to do BOTH the shambler +health and +damage upgrade, AND Morale.  NO-THANK-YOU.  Not only is the Morale skill not better than me spending my other skill points on Absorb and Mulch, but it's not better than the shambler-only upgrade!
Sure the Morale upgrade will effect minotaurs, siege archers, and priests, but you don't really have numbers of them to matter as much as your Night Walkers/Yeti/Shamblers.

In my opinion, the minion upgrading skills should go away and be replaced with something more useful.  Why not just make Morale different for each Demigod?
I just couldn't see putting points into Morale.  While I might use the minion buff skills for my specific minions, I wouldn't put points in Morale because putting points in one of my non-minion skills would be much better spent.

I mean, it's a good thing that theres enough useful skills that you wouldn't put points in Moral.. but at the same time it's like something is lacking, because it's wasted room on the skill bar.

Maybe if Moral gave specific buffs to different types of units..(priests, minotaurs, siege archers, general specific)  But even still I don't think that'd make it useful

Dr. Acula Minion Skills
They take up too many points to be useful IMO, and the joint one is bad.
First of all, I think both of Dr. Acula minion skills should cap at level 3, with having the same effect as level 4 does currently.  That'd considerably improve them.  And the joint skill that requires both needs to be better.   Right now, I would not spend 9 points on this, usually. :/  Except as like.. some sort of joke.  Why not have them heal Dr. Acula instead?..

Or how about replacing the +life per second on his portion skill with a 3/6/9% life leach aura to all allies within 20 range, 10/20/30% for minions, instead of the 10% at the last level, and making the joint skill for night walkers make them deal the damage of life night walkers leach whenever they leach life?  It'd synergize nicely with suggested changes to Haubek of Life.

Or something. I don't know.  The joint skill right now is bad, and 8 points to max them completely is bleh too, unless you make the 4th level on each give a really nice bonus.

Night Crawlers also fail to attack move even when their move speed is really high!   Oak's seem to do it fine.
Personally i'd prefer Nightcrawlers have a really short range spitting attack that can be used while moving..

Sedna
While I'm on the subject of Generals, can Sedna's pounce please leap at the target?  Then she wouldn't REALLY need tele, but since it's targeted it's not always useful for running away.  That'd be really awesome.