@Elderon37: I understand the points you're trying to make, and if this is indeed the reason they can't do a quick revert while coming up with a better solution then someone at BioWare should either make that statement or pass it along to Mako to make. Now despite your specific assumptions on the problem with a rollback, I think there's still a work around. Specifically with the ME2 special abilities issue. There is literally a system already in place to tell the game a squadmate is loyal outside of the in-game achievements list (I really wish they'd called them accomplishments or something to avoid confusion with the actual Xbox achievements). If they rolled the patch back & then did a hotfix that implemented a check for the game to compare your squad list for loyalty, and if found, trigger the in-game achievement that should then trigger the abilities being available. It could work as a Band-Aid for the post update save file issue until they can dig deep enough, and test thoroughly enough, to properly fix the game's issues. That temp fix shouldn't be intrusive enough to cause issues with the game's other systems. It wouldn't solve my issue of not being able to unlock Paramour II/III (and likely Insanity II/III), but I do have saves before ME1 romance & final fight. Even if replaying them doesn't properly trigger the in-game tracker in my ME2 playthrough, there was a work around in the pre-patch version that would allow me to get those achievements. In fact, I wouldn't be surprised if the devs desire to "fix" an exploit that was in the player's favor is the reason this whole in-game achievements screw up happened in the first place. Paramour/Insanity II/III Xbox achievements weren't unlocking for players, who then used a work around to pop them. Instead of focusing on the actual problem, they tried to plug a loophole, and broke the game for even more people.
I may not be a programmer, but I do know some things about people. Really smart people, analytical people, logic focused people can sometimes have a tendancy to overthink things and/or focus on a specific thing to the exclusion of all else. This can lead to focus so hard on the problems that a solution is either never found or found so late that the damage is already done (in this case, customer goodwill for a company that's already had some knocks). My favorite is getting so locked in to finding the exact reason for a bug that anykind of work around is never even explored. This can be a good thing at times, but not with something like this that's under a time crunch. If it were pre-release, or a non-gamebreaking issue, then dig as far as your employers will tolerate.
Even if the hotfix thing couldn't be done, rolling this update back as soon as they realized so many players were having these issues would've allowed those players to have gone back to a pre-patch save or simply started over if they didn't have one, or then have the OPTION to wait for a proper patch. Yes, some would've been upset with the set back, but they would have also been able to play the damn game for the last 2-3 weeks. In my opinion, some players being mad they lost 'X' number of hours of progression, but now being able to fully play the game far outweighs a lot of players getting pissed off because their game has been broken & unplayable for 3 weeks (doesn't matter if you or some the devs don't consider it "unplayable", it's obvious that alot of players have put the game on hold, myself included).