Halo 1 was unfucked weeks before launch because Bungie was never sure what exactly they wanted it to be (which is understandable for a first game in a franchise), Halo 2 was never unfucked because it just straight up released unfinished due to Bungie's ambition colliding head on with the reality of game development, and then Halo 3, ODST and Reach had decent enough developments. All five games are pretty much legendary outside of some grumbling about 2's difficulty issues, 3's length, and Reach's gameplay choices.
Meanwhile, 343 hasn't remotely reached that pedigree. So when they've had three games to get their shit together after people have pointed out they have severe issues with art design, randomly regressing from established Bungie features, and having their games not have tons of fucking bugs, seeing those issues crop up in Infinite while the game is going through a reported development hell, with multiple leads leaving, does not inspire confidence.