FALSE.
Act 1 & 2 were the meat of the game, Act 3 was a failed attempt at noir-stealth butchered by a reverse escort mission, followed by Big Mama shitting on the vastly superior MGS3's cast of characters by retconning them into monsters, a fun on-rails motorcycle chase and a forgettable boss battle (sadly almost all of them were, a real letdown).
Act 4 was a nice throwback but replaced soldiers with small Iz characters from the Maxx, and the plot really started shitting itself around there. Act 5 barely happened.
there's definitely more than 1 path (BBE mode shows you this) but it's not nearly as replayable as you're making it out to be either, and compared to previous iterations, it tried very little different overall.
it didn't need a "perfect ending", but it did need an ending with the balls to actually resolve things, rather than leave giant plotholes and create more ambiguity in what felt like a poorly edited fanfic. i respect that it was tasked with tying up the loose threads from 2 (no small task) but it didn't let you play enough past act 2, and again plotwise it shat the bed decisively. been playing MG since NES days, im hoping ground zeroes can help heal the wounds (peace walker tried but wasnt enough).
are you guys actually playing console games? this isn't even top 10, and again, that's coming from a big MGS stan.