Carroll isn't ready for us yet, doubt he will be ready next season either.
Yes, when we had Modric, VDV we got to that point of playing triangles very well, however our midfield did have bad days then as well.
I'm thinking differently these days..
Bentaleb coming on has proved you don't have to have loads of experience and be some beast of a man to add something to our squad. He's done phenominal for a teenager making his debut for our squad. Carroll (who has more quality than Bentaleb) would undoubtedly come in and instantly be one of the top 3 passers in the team. He would also constantly provide options for our defenders looking to play it out of defense (which has been a problem recently in our new 4-4-2 as other posters have noted).
Honestly with a midfield of Eriksen, Carroll, and one of our 15 midfield destroyers, we would crush teams.
Eriksen has proved if you get the ball to him in the attacking 3rd he'll create chances. Carroll has the pass and move ability we're missing right now and has proved (albeit in the Championship) if he's playing beside a more defensive player (for him Barton this season who is half the player of Sandro/Capoue) he is more than capable of doing the job. We have the quality around him, alls left to do is recall him from his loan.
Bring him back and give him the chance Timmy!! He is more than ready!