It's mostly a matter of how wrecked you mind leaving the person MFIing.
Ramza is technically superior, but in the end, you're going to have to boost his Brave back up(And, if you're not doing it all at once for whatever reason, back down later). Yeah, easy to do casually, but there'll either be battles you have to do it in extra, or you'll have to put up with low Brave Ramza for a few fights.
Whereas, if you consider (Rafa original, Malak here) not worth your time, hey, just drop them and leave them. Less work, if you don't care about the character enough to boost the Brave again. Also, you don't have to worry about not doing all your Move-Find at once this way.
Even if you don't find Ramza useful(I can't recall ever seeing someone say that), his forced nature makes it uncomfortable to leave him low on Brave. If nothing else, you might want to go beat the game again afterwards. (I suppose he might be running a no-Brave Reaction skill and no Brave weapons and it wouldn't matter much then, but.)