I'd appreciate if more noticeable attack warning was added, because right now those cracks on the ground simply blend in. Ice cubes are especially bad, since their freeze cloud renders those cracks pretty much invisible.
In fact, it would be even better if attack was modified into a line of spikes emerging from the ground, much like retrode's explosions (or a lurker from Starcraft). That would be more visible AND more dangerous.
NO MORE NERFS!
The normal levels in the game are to easy already. Certain monsters like knockers and scuttlebots need to be buffed and NOTHING should be nerfed.