I don't think they are becoming meaningless, but they are situational. They always have been really. It's just that now there is less bloat in the talent trees and the act of changing them is less arduous.
It seems that Blizz is afraid of GOOD talents. If you give us choices...one will be the best. We will gravitate towards that.
How do they respond to popular talents?
Nerf bat. Ruining something that was good or had a purpose.
How should they respond?
Create an environment or challenge that makes the other talents attractive.
Just get rid of talents. Give us the tool box you expect us to have and lets get on with it already.
Several fights in Cata showed how flawed being dependent on a pet was. Hey here's an option to go petless when needed.
People liked it? Nerf.
Hey we took away all your instants and most of your cc's? Here is an option to move with a cost.
People liked it? Nerf.