First of all, where the hell did that last line come from? I click on Reply with Quote and I got an extra line? I am freaked out.
You argue finances, we argue football. Plus how do you even know that Valencia are better off?
I don't, for all I know Piatti suffers a career ending injury in the first game of the season and in which case they will seriously miss Mata.
But based on their performances last season and in pre-season, while Mata was very much one of the main players for them, he was much more a cog in the machine, so to speak, than a dominant force. He was certainly a lot less individually dominant than Villa and Silva were, and yet last season without those two Valencia actually closed the gap on Real Madrid (assuming that, as most of your ilk claim, it wasn't that Madrid got worse, because of course there's no way Madrid didn't improve with the brilliant Mourinho compared to Pellegrini, who you and Beast reviled), won the same amount of games and had the same amount of points. They scored less goals but their goal difference was only 1 less, if anything the sale of Silva and Villa made them more
balanced.
Valencia made a lot of impressive attacking signings this summer. Piatti was arguably the La Liga steal of the season, he's been one of the most consistently good wingers in La Liga for a while now and at 22 playing for a much better team, there's a good chance he will be even better this year. He's been on fire in pre-season. While Canales is raw, before Madrid got their hands on him he was hyped as one of the best new talents to come out of Spain and on a team where he will actually have a role he could easily rediscover his racing form.
Add in Rami, a better defender than any CB Valencia has had since Albiol wasn't a disaster, and a young team that will have experience playing together for one more year, and you have a squad that, even without Mata and without the money reinvested, is arguably still stronger than it was last year. And if a fraction of that money reinforces the defense further, even if it's only bringing back Own Goal Albiol, you have a team that is deeper and more balanced than they were before.
The following players can play in Mata's role:
Piatti
Jonas
Feghouli
Canales
Bernat
Jordi Alba (he's being converted to a more defensive player though, but he spent most of his career as a winger)
That's a lot of mostly young talent. Chances are one of them will be able to make the most of this opportunity.