If you're playing remotely efficiently, probably Innes. I prefer taking it slow and grinding, particularly in fe8 where there's plenty opportunity to do so, and I prefer Neimi for being able to promote to a mounted unit that can use swords. Although honestly in most cases past early game, I end up using magic users over archers anyway. There's just very little an archer can do that a decent magic user can't meanwhile magic users have better range, staff use after promotion (or before in the case of healers), and any unit that can promote to bishop gets a massive damage bonus against monsters which make up a lot of fe8's enemy units.
I do prefer Innes on support conversation front though, I'll admit.