Yeah, Timed Exclusives are all the rage these days.
I suspect that ideally developers would make the game for the highest spec console first, and then make the version for the lower spec, which requires more time optimising. It may seem unfair to the lower spec console to get the games later, but whenever I saw an exclusive for Xbox turn up on PS2, the game had usually improved a lot and was very close to the Xbox original in speed and such.
We'll see what happens with the new machines. If indeed discspace becomes an issue, that could be a reason to develop on PS3 first, especially if you don't have to worry about not having a HDD. On the other hand if you are developing a game that's also suitable for PC, you might choose to go for the 360 and XNA first. And then of course there are companies like EA which have two big teams, one working on a 360 engine, the other on a PS3 engine.
I suspect that ideally developers would make the game for the highest spec console first, and then make the version for the lower spec, which requires more time optimising. It may seem unfair to the lower spec console to get the games later, but whenever I saw an exclusive for Xbox turn up on PS2, the game had usually improved a lot and was very close to the Xbox original in speed and such.
We'll see what happens with the new machines. If indeed discspace becomes an issue, that could be a reason to develop on PS3 first, especially if you don't have to worry about not having a HDD. On the other hand if you are developing a game that's also suitable for PC, you might choose to go for the 360 and XNA first. And then of course there are companies like EA which have two big teams, one working on a 360 engine, the other on a PS3 engine.