First of all, I never thought of Silva as a 'big' name like lets say CR, Ibra or Kaka. I agree that he's injury prone, and that is a problem. And I do base my choice on Silvas last 2-3 seasons. And yes, Mata has been playing very good for Valencia this season.
But it's not easy cause' we still don't know if we will buy a CM backup, if Eto'o stays or if we are going after a DM and play Busquets as backup for CM. These are variables that only Txiki and Pep know atm. When more pieces fall into place it will be easier to argue if this or that player fits our needs best.
Anyway, it's hard discussing this matter cause' you seem to be very sure that Mata is the best option for our left wing (or at least a better choice than Silva). But playing against Getafe or Deportivo is one thing, CL is another. And I just haven't seen enough of Mata on the 'big' stages yet. Just by looking at Confed it's obvious Mata has some more work to do before he could be a starter for us.
You can't base a player on the odd start for Spain in the Confederations Cup...people have good & bad performances in tournaments all the time...Bojan has played crap in the U-21's...i'd hardly play that means he's not good enough to be in our squad, or even our team, i'd instead look towards the performances he made against Mallorca and Depor, the teams you say performance dont matter against, but teams like them make up the vast majority of the calendar, and are probably the most important games...You cant win a championship winning just against Real, Villarreal and Sevilla, you win it against the Depor's and Mallorca's...
So Mata's performances in the Confed cup which have hardly been aweful doesn't mean anything about how good he is. Silva hasn't been very good there either, so if your going to say Mata isn't ready, neither is Silva...Plus Silva came in in a top Valencia team...and has declined with that team whilst Mata and Villa have kept firing even when the team was playing shit. Silva hasn't improved since his goal against Chelsea 3-4 years ago...and thats something most people would admit to...
If I am for Mata, you are equally for Silva tbh, pointing to Mata's confederation cup performances but ignoring Silva's ones which arguably have been worse...They are both very good players, but its down to what we need, we do seem to want a LW to at least rotate with Henry...and for that Mata suites us alot more than Silva does, he's quick, direct and deadly infront of goal, everything people LOVE Messi for, but he also has shown throughout his career he's adaptable and can play a variety of roles...