I personally find troops to be relatively useful as damage soaks and distractions for roaming enemies. This may be because I generally only find two or three champions to recruit in a given game - champion density seems amazingly sparse - and some of these have absolutely ridiculous recruitment fees (I once found one who wanted more than 3000 gildar for his signing bonus).
That being said, I think that troops could feel more useful if the level-up bonus was switched from +accuracy and +health to being +accuracy and +dodge, with a lower limit enforced for the hit-chance. You could still end up with high-level units that are essentially unkillable by low-level units, but you would at least do some harm when you successfully hit the target. The way it is now, you have a champion or two with a lot of health who usually dodge attacks and also usually only take hits for three or four points of damage, which can basically be ignored. This is then compounded by the fact that the champions should usually hit their targets, and if they have weapons like the lightning hammers, they are going to be hitting for much more damage than they will receive - although this is an imbalance in the weapon.
Despite the above, I don't think Stardock is going to switch the +health on level-up for +dodge on level-up - this is simply something that I feel would be better, mainly because you can set a limit on the hit chance and then balance for an average number of hits to kill for certain ratios of attacker accuracy and defender dodge, whereas units which have constantly growing health pools simply take longer to kill.
