iaido is going to be far faster then beating someone with the sheathed sword even without magical powers being involved. it's not exactly a slow way of fighting.
*******sighhhhhhhhhhh*********
Then what makes you think that Vergil's strikes are "Faster Than Light" in the first place?
And, as TwoXAcross (that name is so hard to write... I'm just going to say "TXA") said, once you go faster than
light, it no longer has mass, therefore it won't be able to do you any harm.
Fine, if a human can do it quickly, than a demon could obviously do it faster... just not so fast that it can escape DmC Dante.
DmC Dante has his Angel Warp, which is almost, if not
just as fast as Vergil's Darkslayer and Iaido strike.
You can argue semantics all day, it wouldn't stop the Angel Warp itself from being less fast.
By the way, Vergil's
recovery time is slow at
best. As soon as he unsheathes Yamato, it doesn't matter if he uses a Darkslayer Warp to cancel out of said recovery time, Dante
would still have no problem catching up to him due to his own tools at his disposal.
Not saying he'll win, but I'm certainly not going to say he'll
definitely lose, either.