The PS4 should have BDXL, 128gb for one disc is absolutely fine.
Movies should be kept on the original 50gb Blu-Ray format so no new Blu-Ray players are needed to watch movies.
The only things that should take advantage of BDXL are the games.
Everybody wins =)
Microsoft should drop the childish games and go with Blu-Ray, Blu-Ray is only just taking off and it will remain the most popular high-def format, if they make a new format then it will just be unfair on the consumers and the high-def format war would become overcomplicated. But then again, that will damage Microsoft's huge ego and they wouldn't be able to gloat about how useless Blu-Ray is anymore.