Heart of Life needs to be nerfed. It's not a god item (Artifact) but it sure plays like one. For most builds it's basically mandatory and no one's gold reserve should be X - 4250 (or less with like the favor bag) every game because an item changes the game so dramatically. Only artifacts deserve that distinction and late-game being OP is mandatory anyway otherwise the game is an infinite stalemate. Anything that appears to use oddball methods to circumvent neglected programming failsafes has to be removed as well (every game makes this mistake) like the idol spam (and before someone jumps in to state the trade-off of the exploit, it doesn't matter as it's been confirmed that GPG will be fixing this).

If Oak is going to have something OP, it should have nothing to do with items and only with his own abilities. I would say that being able to suicide rush (Last Stand) on Fortress games is broken because you cannot counter invincibility. Don't allow his attacks to do structure damage while invincible and that takes care of it. There are plenty of counters for a lot of the OP you mentioned. Some of those OP abilities you mention also come at very high costs (like QoT sucking balls 1v1 offensively). They only appear OP if you are playing stupid. That means playing into their strengths.

OP is OP.

don't forget that this game is overpowered for half of everyones computers...(not mine) 

Heart of life is not really op, as it can only be used OUT of battle. it wont affect actual battles, will only shorten the interval between them. If you let the opponent get away, he use HOL then come back 10 seconds later again. for 4500 gold this is kinda balanced i think. since 4500 gold is alot, really, and by this time, the game could(should) have been more or less decided anyway. At least the way i play. most games are over under 20 minutes of gametime. Perhaps increase the cooldown to 1 minute or so, up from 45 secs. This would make it so after one failed battle (HOL user flees, uses it, goes back into fight), if he lost this one as well and fled, he could not use it again and come back so fast again, since the timer would still have some time left ticking... so he might as well run to the base crystal this time and get some shopping done as well.

The game records damage dealt, demigods killed, buildings killed, deaths and healing done.

Hopefully Stardock/GPG records all this and compares it to the ranking players list.

After a few weeks, if a pattern emerges, Stardock/GPG will be able to tell what is OP and what is not and make the appropriate changes.

I don't believe the Original Poster has read up on some of the more in-depth reports.

Spit is too strong because it does comparable damage to structures as uproot, which is an ability that ONLY targets structures. Its DoT allows you to set it and forget it in the same way. You could argue Uproot should then be buffed, but I like that she has a hard time killing demigods but destroys structures and creeps.  Let Spit not be able to target buildings.

Expanding on that, each demigod, I feel, ought to have 2 out of 3.  Anti-Demigod, anti-creep, anti-structure, and then of course some place on the offense vs defense spectrum.  Some, like Regulus, have all 3.  Snipe is a great demigod killer, mines and/or AF are great at creeping, and his range allows him to kill towers and forts without risk of personal injury, making him great at that as well.

There's also lots of crappy skills, for instance Reg's lvl 15 at the end of the Snipe progression.  The proc rate is so small, it may as well not exist.  No proc rate should be under 5% (1 in 20) and even that is pretty low.

There's lots of great arguments for tweaking abilities to ensure that the demigod fulfills the roles it was meant to be capable of.

And for that matter HoL shouldn't allow movement while its healing you.  Right now, you can kite someone while healing yourself to full life for a trinket you can buy maybe 10-15 minutes in, with a very VERY small cooldown.  CD should be upgraded to 2 minutes at least, as well, or gold cost should go up.  A lot of items are significantly better than others, some are downright worthless, others some would argue are absolutely necessary.  The items in this game are by leaps and bounds the most in need of tweaks.