I don't see how 360 owners are getting an "incomplete" version of GTAIV because they don't have a mandatory install (mind you, it's not like you have the option on the PS3 version either).
Do I agree there should be an option, since the 360 could handle it? Yes.
But just because that option doesn't exist, means the 360 owners are getting some gimped version - we are getting the extra content afterall. Which, to me, would mean we're still getting the "complete" version, just without an extra option that not everyone could take advantage of.
Back from the dead, I'm afraid.