Wyll strikes me as a bit of an own goal. First Larian made him a melee warlock with no melee capability and then wondered why he's not all that popular. Well...
Then they fix him for the release by making him work better. And then they add that he is kind of unable to be in the same party as Karlach, just your friendly neighborhood tiefling rage monster.
So I can either have a (literally) smoking hot skull-cracking barbarian that should work okay as a roadblock, providing a fair bit of utility for the party, or I can have Mr Drama Queen who really only works as a striker, which means someone has to tank for him, and he can't really provide mage services, and he's not a rogue, and he also doesn't do cleric stuff.
I don't know. I'm sort of thinking that Wyll will contribute mainly by donating his spare tadpole to the cause.