Martin's supposedly seeking a four year deal at $9-10M per year, and I don't think I'd do that if I were the Yankees. Here's how Martin and some of the catchers in the Yankee organization project according to CAIRO in 2013.
BR: Linear weights batting runs
If you use BR/650 as a crude method of comparing them on offense you can see the difference between Martin and the others. Now a catcher doesn't get 650 PA in a season so drop that down some, maybe by about 10%.
Sanchez is probably at least two years away, but in two years he may be a better hitter than Martin and he won't be costing you $10M per year. On offense alone, Cervelli projects to be less than one win worse than Martin. I think CAIRO may be optimistic on Romine, but Stewart's projection doesn't seem that bad and it's only about a win worse than Martin. I don't know why Whiteside was even acquired, although perhaps he's a phenomenal defensive catcher in ways that aren't captured by his average SB/CS numbers (30.5%).
And that segues into a consideration that is ignored when looking at offensive projections. In traditional defensive numbers Martin's nothing special, but as people have tried to quantify a catcher's impact on pitch framing there's evidence Martin's one of the best in the league. Does that add a win to his value? It could. And it's likely none of the other candidates will be that good, now or in a few years.
Still, I find it hard to reconcile signing Martin for more than two years while trying to maintain a lower payroll. Especially if the Yankees intend to sign Robinson Cano after 2013.