this question was troubling me as a tremendous nonsense issue of the game.
please turn the mercs a little bit more like the hero.
issues I find aren't great about the dycotomy hero/mercenaries:
.there's really not much sense in regular accessories/weapons/armors becoming bound to the different chars. not even rare ones should, only epic ones.
.the issue brought by Geomaticus -
http://forum.imperialhero.org/int/index.php?topic=2992.0 .if you discard one of the mercs at fight 2 of multistage dungeon why can't you call him back for a later fight when all the rest are a bit wasted already? if the merc would be left "behind" it would be no trouble for him to cross all the "cleansed" dungeons and join a later fight, I guess
.when a merc level up we should choose his progress as with the main char, and he should also receive a "skill" upgrade, also being decided by us where to invest, amongst all the possible ones in his own class and tier, after all, he's being paid by us ^^ we decide what's best for him/us.
.when you upgrade some merc's tier, but your char is a tier behind... there should be at least one accessible province allowing healing for him ( or at least "ressurection" ).