Absolutely not. And I'll explain why (although I'm not a Yankee fan)
1) Salary caps don't work. The main reason to justify them is they promote competitive balance. Well, in the NBA the Celtics and Lakers were the top teams before the salary cap was imposed, and the Celtics and Lakers are pretty much the top teams now. In the NHL it was the Red Wings. Well, the Wings have gone to the Stanley Cup finals the last two years. The NFL had competitve balance before it imposed the cap and it continues to have competitive balance with the cap. They achieve that by scheduling - weak teams get to play lots of other weak teams and suddenly their record is better.
2) A salary cap is just an artificial line that divides how much the owners have to pay out and how much they get to keep. So implementing a salary cap just helps owners keep more for themselves. Personally, when I buy a ticket, I'm paying to see the players not the owner.
3) Salary caps punish success and reward failure. I have a fundamental problem with that.
Now, does baseball economics cause some problems? Yes, I'll definitely agree with that - but a salary cap is not the solution. I think the solution is for baseball to improve revenue sharing - continue the luxury tax and follow some of the NFL's lead on sharing of television revenue. And couple that with minimum salaries so that the Pittsburgh's and Kansas City's stop selling their young talent and actually build competitive teams.