calandale - Perhaps what is needed is an armor proficiency stat. Like in the Elder Scrolls games where you can use heavy, light, or medium armor to full potential. For M&B, this could be changed to only light and heavy, or metal and fabric. Horses could have a strength stat that would govern how much of an encumbered character they could carry. A heavier character would slow weaker horses down and a lighter one would let the horse go at its fastest speed. War horses would have a high strength stat, so their charge would not be as affected by a lance wielding character in Black Armor.
The idea for finger guards is cool, too. If M&B ever adopts a left gauntlet, right gauntlet system, that would be a great item.
Eird-Way - If such a change would ruin a person's fun, then perhaps a juggernaut archer would be possible if penalties were removed but leather gloves would offer benefits. That way, the person who wanted the super-knight could have their way with heavy gauntlets, while archers could still have a bit of a bonus. Of course, it's all up to the developers. =)