I have not given Wyll a chance, I'm playing a warlock so I see no point in having him in my party, and unfortunately, I get progressively less interested in characters that are not in my party.
That and fiendlock is the most uninteresting pact for my taste. That said, he seemed alright during his introduction and the few times I talked to him.
I played Wyll with a custom warlock and had a blast. Specifically, an eldritch blast. Several, actually. All day every day. It was pretty fun being able to bounce opponents around with two warlocks.