You just answered with exactly what I said... you basically must do the frost nova -> rain of ice -> deep freeze combo... otherwise you will not be a threat to anyone, or kill anything (as Ice TB).
Ergo 'one trick pony', the only difficulty in the whole thing is getting people close enough to you so you can pull it off. That changes in team play however when Ice TB and Rook team up for some sweet hammer slam and stun combos.
I am terrified of the Ice TB until it misses it's frost nova, at which point it becomes a frosty pinata... there is something wrong there.
Well, you don't necessarily have to do the first two in a specific order, since it only matters that you stack the effects. I agree, though, that the mechanic does technically put the Ice TB into a certain mode of operation, and it could be even more fun / interesting. But my point is that even so it's better than the alternative because it rewards the player for timing and using skills in conjunction with one another, instead of just mixing and matching.
In other words, even if every battle with an Ice TB is nova / rain / deep freeze (or rain / nova / df) it's still more interesting than combat where it doesn't matter what order they use the skills in.
The truth is, it's really difficult to make deep, interesting combat when each Demigod has only a few active abilities available at a time, but we need to work with what we have, I suppose. Add more conditions to skills, make them work differently when used in different orders or in different places in relation to the enemy or the map. Introduce more decision making into combat as opposed to simply "when do i attack? when do i retreat? when do i use this potion? when do i use my nuke?"
I'd also like to see more items with active abilities that are more than just an added nuke or a health regen.
