Microsoft have been operating this way for a long time, putting pressure on developers with a simultaneous release and content parity clause. Annoying as one of the strengths of the ps3 over 360 was the storage capacity of blu-ray discs. Many games could have been enhanced on ps3 but weren't probably due to this Microsoft clause. Microsoft may allow games at their discretion. The reality seemed to be major games may get through with PS3 enhancements but not lesser games.
You only have to look at the size of ps3 games to see the issue. The minimum capacity is 25GB (50GB for dual layer) yet most ps3 games are only about 8-9GB same as xbox 360 discs. In many games a huge amount of additional content could have been put on the ps3 disc. Multiplayer maps or whatever. Also the PS3 has the capacity to show much enhanced pre-rendered movie sequences far superior to the 360 engine generated sequences but this is lacking in most games and really something all ps3 games should have.
There may come a time this generation where Microsoft are desperate for every game they can get and these rules will impact their success. Ultimately the ps4 is already hugely ahead just after launch and is clearly going to be the major format this generation. So many developers may decide not to develop for xbox one if Microsoft make it difficult for them.
