I now have three dual wielding warriors in the early stages of the game: a dual-class Yoshimo dual wielding the blade of roses and sunfyre, Minsc dual wielding a mace +2 and the flail of ages, and the player character dual wielding axes waiting for a katana upgrade. With Keldorn wielding Lithacor it means everyone has a pretty bad AC. Question is, is there such a thing as too many dual wielders? I will miss out on the shields, but shouldn't the damage output more than make up for that? Any strategies relating to dual wielding?

Don't worry about if you dual wield
your opponent will be dead before he can even see your AC

i've got 4 dualwielders aswell in my party
so

I don't just dual wield
i dual post as well
damn do i feel fuxcked

I've never been a great fan of dual wielding. For some reason, I just prefer the use of shields. I've got myself using two-handers, Korgan with an axe (usually an enchanted throwing axe) and a shield, Jaheira with a sling and a shield, Viconia with a flail and a shield, etc., and they all make good tanks with nice, low ACs. Me, I've got stoneskin and mirror image. We all kill plenty fast, as well.

Dual-wielding rocks. I have Valygar with the Celestial fury and Crom Faeyr and he can kill my entire party, Carsomyr wielding Keldorn included, with barely a scratch. However, you have too many fighter types. 2 is sufficient for any fight, as magic is king at this level of AD&D rules.

Well, Yoshimo will eventually play the role of the archer except on those instances he is needed for close combat (i.e., dragon slaying) and my character will eventually do more casting and less pummelling (though it's hard to resist meleeing with the celestial fury now in hand).