Open Solaris could benefit, but the biggest beneficiaries I see if Linux stumbles are the BSD people. The BSD license is much, much less restrictive. Basically, you can do whatever the hell you want with the code; you don't even have to make your changes public. You can make proprietary products with it. The only stipulation is that you give the original code writers credit when branching off. That's it.
Probabally correct. Apple has shown BSD is more than up to the task.. Still I dont think 'linux will stumble' if anything this will finally get the albatross (stallman) off the neck of Linux. In the event of a split all of the code license under gpl2 will stay 2 and improvements can be applied by anyone.
BSD just doesn't have any significant commercial offerings except Apple, which requires a purchase of the Apple hardware and therefore significantly hampers distribution. OpenSolaris is already seeing a heightened interest since the GPL controversy erupted, there was a story just a couple of weeks ago that Google is considering if not preparing to switch to OpenSolaris from Linux, which would be the conversion of the largest Linux user in the world.