...They perma-died like all other trained units? So they level like champions, but die like trained units.
There's be a risk/reward profile in investing in henchmen that would make them less OP, I'd guess. You can still create stacks of ridiculous henchmen but you'll need to make sure they live - otherwise all that time and effort is gone.
I'm guessing this was suggested already, but makes sense to me.
