Both these suggestions are minor troop AI changes, but none of them are really practical.
Part of the game is knowing how to distract every defence in such a way that you can send in another troop to take that defence down.
Remember, that if YOUR troops float over or walk around the lava pools and avoid defences that will kill them, then your OPPONENTS troops will do the same. You would be right back here complaining about something else in no time.
The Troop AI is probably
a simple A+ path finding algorithm .. shortest route to the nearest defence or building, with a priority break condition telling the troop to stop moving and do something else if a guard house troop is within range (and attacking).
The AI is not build to think "hey, if I stop here for 20ms, I will avoid getting beaten by the multi mortar that will shoot 80ms after I've destroyed the thing I'm beating at right now"
It's not impossible to do, but .. would it be fun to get BEATEN by something like that?
/Affront