Yeah, you can get exp for just defending half a turn so it's not a big problem. Everyone usually gets screentime just because of enemy weaknesses, but kimarhi kinds of doesn't have a specific enemy he's strong against so he's forgotten about more often.

I kind of think the exp sharing in ffx is dumb anyway. Considering most characters are gonna be needed most of the time, everyone should either just have gotten the same exp, or at least be given 50% exp if they weren't used. That way, the people you use remain strongest, but you don't have to spend annoying amounts of time to make certain characters catch up.