Erebus
I think his base move speed needs to be increased to the same as Unclean Beast's. Not like he'd be as fast then, since no movespeed buff skill. And a small base DPS increase. His skills are actually rather good for the most part, except for the minions related ones.
He'd also be better if his potion skill was 4/7/10% life leach aura, not 0/0/10%.
Queen of Thorns
Not sure how you think she's underpowered. She's one of the best.
Shamblers: Well.. It's hard to say. Have you tried these with open form? The armor reduction from her AoE can makes these pretty useful
They could use an attack speed inrease, but I'd hate to see thier health nerfed. They already die really easy to some aoe. :/ Yeti's and Shamblers need to not die easy from AoE. I think Shamblers are simply weak like all the others, and better +minion stats items would make them fine. Right now +minion stats items are useless, so so are sort of minions.
It's all minion builds that need a buff, not just Shamblers, so I don't really understand the just singling out shamblers on this.. I think Shamblers right now at the best of the minions, due to QoT having slow, range and armor reduction.
I do like the Idea of all the Minions having abilities, like you describe. Not sure about that specific ones. Why not items that give the minions Abilities? "General wand - Shamblers gain .... Yeti's gain .... Nightwalkers gain .... Spirits gain..." Then I can choose from one of those items on what ability I want my Shamblers to have.
Brambles: This is currently far too good in the first few levels of the game, ESPECIALLY in 2vs2. In 2vs2, QoT and an assassin is pretty much unstoppable with having Brambles on herself and an ally, essentially having as much HP as if there were a 3rd person.
It needs to have it's absorb adjusted to 450/700/950/1200, or its mana cost increased 25% for early levels.
Mulch: The mana cost at higher levels needs to be increased to 550 or so.
Oak
He's the worst. Worse than Erebus if you know how to play. I guess some disagree who is 7th worse, and who is 8th worse, but people tend to agree that Oak is either 7th or 8th still.
He mostly suffers early on. He doesn't become good unless you manage to get to level 8 or so without being far behind the other players. It's his lvl 1-3 skills that need buffed.
I think with Oak, all his skills are pretty nicely designed. But no 3 of them really comes together as something powerful. There aren't really much of builds for him. . Yeah, spirits go together well with Soul Power, but it feels like you need more than 1 other skill to go with those two. :/
Really it seems to me like Soul Power should basically be a part of his raise dead skill, then he has more skill points to use for 2 others skills along with, instead of just 1 other. Or Soul powers effects being on an item would make for a nice item, but then possibly too good on Erebus. I'unno. Or Soul power being max of 2 levels and 25/50 would make it easier to spread points out with him.
Starting Stats: 50 more armor would help.
Shield: 3 seconds is just rather.. useless. If there were a way to easily self-cast on yourself (like click portrait, or double click) you could at least use it to sort of avoid skills, like snipe, hammer slam, etc.
But what's worse, is at level 2, it's only an increase to 4 seconds. It really should be 4/5/6/../.. with at level 2 it giving another bonus, like significantly increased (15-25) MPS and/or HPS for the next 30 seconds. That'd be 450 health and/or 450 mana at 15 each, or 750 for 25 per second increased. That'd make shield 2 good, and make him better at level 4, for a start.
Rally: Should give a 20% speed buff or so as well, trigger even if you just got an assist, and be level 10 requirement, not 15. This would be very useful in 5vs5's and 4vs4's then. Maybe REALLY good then, but it requires a tricky condition to get the effect.
Surge of Faith: The buffing of allies part of it should be range 20. It's just the same range as the damage, isn't it? I haven't checked so I could be wrong here.
Penitance: It might be more useful early on if the damage increase was 20% across all levels, and the duration fixed at 7 seconds. The damage increases later game, on its own, because you're doing more damage. Early on there isn't much damage to increase. The progression for movespeed decrease is fine. Instead have the cooldown decrease over levels. 12/10/8/6 seconds.
The Rook
Starting stats: His +500 starting hp is fine. The 2k more at level 20 is not. He should start at 500 more than the others, and end with 500 more.
Towers: I think they just need a minimum distance from each other.. like 12-15 at least. 8 is fine, just not all clumped up on one flag.
Torchbearer
Deep Freeze: Shatter being on a skill that is already quite powerful is just what's silly. :/ Deep freeze is trying to do too many good things at once, and part of it is bugged. Deep freeze in its current state just isn't really balancable, imo..
Frost Nova: I think 3 seconds is just too long even at least 15. And it should have a lower cast time. Isn't it way faster cast than erebus' AoE stun? I see no reason why it should be when TB has the advantage of range, more damage, etc.. And Erebus stun i think is smaller AoE.
So yeah, I'd just like the level 3 effect on it still 2 seconds, and just giving another bonus like damage or something. (but not much, just like 300)
If the cast time were slower, there would be more things you can do to react, like stun the TB first.
I believe it is .9 sec cast. It should be 1.5sec if it is. Correct me if I'm wrong.
Ring of Fire Buff: I don't see the point in meteor like people sugest, because rain of ice basically does what it would do then. Ring of purpose is supposed to put a DoT around you to keep melee from attacking you. However the damage is so low now, that anyone can just stand in it against a fire TB.
It does need more DPS, or some other bonus effect like lowering your cooldowns of skills while you're standing within it.
I agree on what are issues with Rook, TB, and Erebus, just not how to fix them. ^^
Also with the slow gloves, they aren't bad on Sedna.. or when you don't spec for a slow. It's just they're ridiculous when combined with UB's slow, or maim, so on.
Just capping slow effect at 33%(before speed buffs) would fix all the problems with slow stacking. Just make hte gloves cost 2.5k, be 20% slow instead of 25%, and lvl1 maim with them woudl be 30% slow. If reg wants 33%, he can get lvl 2 maim. But maim needs adjusted too..