Halo was tanking in terms of SP quality before 343i took over. Halo 3 released and to me was completely destroyed by COD 4 MW as a singleplayer experience. I was thinking how in the hell was a military shooter more epic than the grand finale for Halo? Didn't matter, to me it was. Halo 3 did not deliver what it promised. Reach was a big step up over Halo 3, but still didn't quite do it for me. Halo 4 is the best campaign in the franchise, with much needed gameplay improvements that Halo 5 took to the next level. Halo 4's story and character development are also unmatched in the franchise. Master Chief and Cortana were expertly handled as characters. You got to see way more depth to both their characters than you ever had before.
Halo 4 to me proved 343i was the right team for Halo. I feel even if Bungie stayed, we'd still be seeing Halo crapped on the way it gets crapped as of late. And many of the same people WERE in fact crapping on Halo when Bungie was in charge of it. It was just the moment Bungie became independent and signed that contract with Activision all of a sudden everybody was labeling Bungie's Halo games as perfect. Well, they were far from it. Once Halo hit the 360, it was never as good as the first 2 games until Halo 4 dropped imo. I can't speak to ODST because I honestly didn't really give it a shot.