I love Wyll's story. I think it's great, and there's obviously so much potential there. I completely disagree with all the comments about his personality being off-putting. All the origin characters have flaws, and that's fine. If anything, it's a mark of good writing.
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Unfortunately, the mechanic of actually playing Wyll doesn't match his excellent story. And that's a huge problem. I hope someone at Larian hears this and can fix the problem. Maybe if they institute a blade pact... but even then they would need to tweak it a bit.
Personally, I think Wyll should have a Pact of the Blade, and I think it should work like this:
1. He uses his Cha in place of Str to fight with a blade,
2. His eldritch blast is not a blast. Instead, it goes through his blade. Meaning he can't do ranged attacks, but his melee damage is weapon + eldritch + hex + Cha (if he takes the appropriate options).
I'd also like to see his stats change.
Take the Wis down to 8, lower his Con to 14, and raise his Dex to 14 and finally, raise his Str by however many points are left.
Just my opinion, but those changes, coupled with Wyll's story, would make him a wonderful inclusion.