While appreciating the theory that it's worth going for the younger player out of two solid options, I can't hack this (Arshavin:Hazard) = (Khedira:Schneiderlin) analogy.
Arshavin was an arrogant dilettante a full ten years older than Hazard. I was already questioning his attitude by summer 2009, let alone 2010.
Khedira's 27, works hard, has plenty of friends in our squad, is accustomed to not being the main star etc. There's no reason he shouldn't be peaking for the duration of the four year contract under discussion.
I suspect if Schneiderlin were available for a £20m fee we'd be in for him, but Southampton are gougers.