What is wrong with having strong female fighter types? So for once the guys are mostly the casters. I'm totally ok with that. I can't envision the game without Lae'zel or Karlach anymore and they are just perfect the way they are. You have a strong Dex fighter with Astarion, who can own a battlefield easily. You will have Minsc later on, who canonically is very strong. Wyll as a Bladelock is a good melee fighter, I don't see the problem here. You can even redpec him and make him a warlock/paladin, if you do like. The only character not made for frontlines here is Gale and maybe Shadowheart ( though she is pretty tough, but I like her more as a caster). I think, that Halsin will be pretty tanky too.
