I never thought much of the sequels, especially the second one. The timing and tone always seemed off to me. I already have it on iTunes, but I may end up getting the first film on disc when it gets an individual release.
I think pretty much all of the major filmmakers of the 70s - Coppola, Friedkin, Scorsese, Lumet, Pakula, Bogdanovich, maybe even Lucas and Spielberg - would be working for HBO, Netflix or Amazon rather than in features, if they were starting out now.
As I'm only really interested in the first one, I'll hold out for a single disc release. I already have it on iTunes, so if the upgrade looks good enough, I may end up just sticking with that.