I think the point of a playbook is that it say, hey, here are some limited choices that support a specific archetype. You've got moves, sure, but also look, gear, advancement, maybe a sex move kind of thing, maybe even names.
If you just have one playbook ... I'm not sure that it's a playbook? Isn't it just "character creation"?
If an Unknown Armies hack wouldn't benefit from specifically-themed sets of character options, niche protection, and etc, then just don't use playbooks. You can still have a convenient one-sheet character sheet that includes all character creation information, but that's not an AW-style playbook, it's just good design.