This strategy might look great on paper, but in reality its quite risky.
Suppose, Microsoft releases Xbox 720 (or whatever) and then patents some of the basic stuff we all expect... Then what? Sony won't be able to use it on their PS4 and might even have to retract existing development.
Or suppose, Xbox720 turns out to be so good that most of the customers don't wait for PS4 at all, then what?
What a lame logic

Billion dollar companies with billion dollar products, you seriously think that MS and Sony would get into that patent war and $hit on these sort of things?
And no, even if xbox is twice as good as ps4, both the consoles will perform equally good, the difference would be extremly minute. Both the consoles are going to stay for nearly a decade, so they'll make good business, don't worry