No really interest on game ... i speak more about the rest of the applications that could benefit about it.
Especially interest on comparison with the open solutions supported on Linux.
Now is ready the OpenGL 4.2 only using proprietary driver.
OpenGL 3.0 is quite ready as open alternative.
Intel Sandy Bridge support OpenGL 3.0.
Intel Ivy Bridge will support OpenGL 3.1.
Intel Haswell perhaps will support only OpenGL 3.2.
Based on Intel cpu and the current state of the open OpenGL on Linux i suppose that once these Cpu are ready, the support for these new standard will be available.

What's New in OpenGL 4.2
The new features are also available individually as ARB extensions, making it possible to support them selectively on pre-OpenGL 4.2 implementations.
So no problem - except performance (given that these news extensions will run on the Cpu instead on the Gpu) - even on all the previous OpenGL standard? Or exist some particular limit on their selective use?

Merry Christmas
Joyeux NoŽl
Frohe Weihnachten
Buon Natale



Note:
I hope google translate doing a good job during the greeting.