TBH i just played Rook against 5 nightmare level AI and with only 3 other AI, but in the end i have 47 kills and only 4 assists. Game time only 30 minutes. I know its not much to say because playing against AI isn't much to show, but it rules out all these arguments that rook is underpowered and sucks.
I'm sure players are going to outsmart him from time to time, but the rook player just need to outsmart the other one in return. Buying the correct items can ensure that he can be just as fast as any other, (the boots that give +50% move, chance when take damage). And honestly, once i reached level 25, i didn't have one point in the structural drain, its almost pointless unless u want to stand still taking damage risking death, just to damage a tower for only 1500? I hit towers for 400-500 which would be faster than draining. I only see this ability being useful for single player if needed.
But honestly, the rock throw has very long range, and i don't know why anyone is complaining about it. Along with the 5 second stun, you all say you can't get his hammer bash off. Pretty sad to be honest.
Also constructing the light tower is important not as a standalone structure, but to link your bases light towers with this one, to conduct a large range light beam jumping from your base, then to your constructed ones through yourself for a lot of damage. Hence the low health reason.
But again like i said, with the correct items he is a ruthless warrior and doesn't need changed at all.