I'm thinking that a possible 3rd subclass for Warlock will involve healing and/or buffing allies as an option. Normally I wouldn't speculate like this, but one line spoken to me by Ikora Rey caught my attention. I don't recall the exact line, but it went something like "[i]Tired of being shot at out there, warlock? The tower could always use more healers.[/i]" Which implies that at least some 'locks do in fact have the ability to heal people.