Vidal has more to his game than Davids, that's not to say i never liked Davids he's still a true great to me, but i don't ever remember him being half as effective going forward as Vidal is
Davids had a lot more ball skills too but the work Vidal puts in every game is insane. Not to mention that Davids was never a leader while I think Vidal should be a shout for captain considering his impact on the team and the way he seems to make everyone comfortable around him. Would have no qualms with him being next in line after Gigi although I know it will probably be Chiellini.