Sanchez here would fit like a glove. It's not very often you see a player fitting so much to a team's plan/mentality/targets.
Assuming that we are going to keep playing the 4-2-3-1, he can play in any of our forward 4 positions (for which right now we have 1 proper backup, Pjaca, and another one if you consider Pjanic as a backup AMC). Very creative and hardworking player. He knows Italy well. And guarantees immediate performance (which Juve targets with Higuain being 29, Buffon leaving, etc). He just looks perfect. And I see him pushing hard to get out of Arsenal in the summer to go somewhere and finally win something.
For the moment being, I don't see us needing another MC if we don't intend to change to a 3 man midfield, Veratti and Tolisso are awesome players but for a 2 man midfield, Pjanic, Marchisio and Khedira as a starters with Rincon, Mandragora and the Uruguayan Boca kid as a backup, look more than enough for now.
Also, Paris does not need him. With Draxler and Di Maria as a starters and Moura as a sub.
Sanchez, a backup LB and maybe another RB (depending on the form of Daniel Alves after the injury) and we are set to go.
Damn, I let my expectations get high this morning.