^ This.
A couple dumb requests:
I feel like a "Teleport" spell to swap the location of two of your troops would be cool as hell, and tactically very deep (while having limited direct "power".
I feel like have special ending if you manage to hit the king with a Level 3 Succubus would be cool (high level succubus are generally kinda pointless, but having them gift a special ending feels like a cool trade off for the investment?)
I feel like a "bomber" skeletonne with bad stats, but high castle damage would be awesome.
Uhhhhh... Oh! and not sure if it's good gameplay, but having a UNIT which grants spying would be cool (possibly replacing the "pay two gold to spy" thing?).
Not sure.
Overall, the game is beutifully balanced, and now I just want other things which mess with the balance in interesting ways.