The problem is the "gimme-ap" build. Its a very specific combination of abilities and talents that can be abused to no end because ap is such a limited resource now. And its best on the rogue thanks to their high damage jump and their massive single-target damage. Flesh sacrifice, Adrenaline, Skin Graft, Executioner has allowed me to consistently kill at least 2 and usually 3 enemies on the first turn my rogue is in range. Which is usually the first turn of the fight.

However, rogues that stick to just the rogue skill set and don't incorporate polymorph are generally not overpowered, I think. Non Elven rogues are similarly less ridiculous, though Elves are the only race with bonus stats that rogues can fully use (bonus crit chance on humans is useless if crit is guaranteed on backstabs).

I think the ultimate problem lies with the changes to ap availability. If you only get 4 ap a then allowing players to mess with that will almost always be abusable. Playing with tiny single digit numbers makes balance too hard, and I don't see the benefit unless you have to use your fingers to keep track of numbers.