I haven't read all 15 pages of the discussion so forgive me if what I say is a repetition of anyone's opinion but...
Seeing as both Dante and Vergil have out-of-this-world awesome looks, I really can't imagine
any actor trying to act as them. So no, cross out live-action for me. Like Luna13 says, as long as the right equipment and team are on the job, we can expect more from CGI than live-action.
LOL @ Lexy's post... yeah, let Keanu be an inanimate object that wouldn't block our views of Dante/Vergil.