Honestly, I don't see a big deal in this so I think I'm going to step away from this after my two cents.
It may be a problem if EVERY game is doing it, but I think most (not all - AKA Hot Shots Golf 5) of these games with required installs (and the large installs) have been these Capcom games. So unless you get all of these games with required hard drive installs and play them at the same time, then it could be a problem and I agree that developers probably shouldn't force it on people. However, it's still a good resource seeing as all PS3's have a hard drive.
I still see installing as an advantage for faster load times and such with 20 minutes and 5gigs being smaller and faster than most recent games for PC (... World Of Warcraft or Fear anybody?) The developers are going to have to look into how to best use it rather than force the space on the smaller hard drives on the PS3.
But even then, there is always the hard drive replacement for the PS3 that's not only easy, but also cheap. Comparing that to a $100 or $180 for a 20gig or 120gig hard drive for the 360, I don't really think replacing your hard drive should be any sort of disadvantage. In fact, I think they should market that feature more along with other little known features of the PS3. Heck, I didn't know that you could reset your resolution settings until recently (like one or two months ago recently) so that you don't have to worry about pre-setting the resolution before you move the PS3 from TV to TV.
Anyway, I'm going to step away now because this is getting old.
