[Balance] Rook does not need abilities/abilities suck.
The rook appears to be overpowered. He is a one-man army slaughtering lower level DGs without even using his abilities. High armor, high hp, high damage.
However on the flip side his abilities are 100% worthless. Lets go over them.
1) Archers/Tower of Light/Treb/Poison -- Useful since nothing better to invest in, auto targeting abilities to kill minotaurs.
2) Hammer slam: SLOW. By the time the hammer slams a BASE rook level 15 does more damage or equal damage by just attacking a DG.
3) Rock throw: Useful to stop enemies from fleeing. A nice bonus that it also does damage...
4) God strength: Yea its good since it adds damage. Nothing else to invest in anyways.
5) Towers: I rather save mana for rock throw. Level 1 useful if structural drain is your prefered skill tree path.
6) Structural Drain: Um... its nice that it heals the rook, thats it. Level 1 tower + this is all you need for healing. However the last part of the ability +150% mana regen is stupid. You waste 600 mana to cast it, and that effect should just say "Reduces the cost of the structural drain to 300" and it would be more useful. Also I can do more damage to a structure with regular attacks than the drain does (without item upgrades)!
In the end since the rook won't get mana items due to money restrictions, its worthless to get tower, hammer slam, structural drain. Just get god strength and shoulder towers. Rook is also heavily overpowered as a base unit.