It was the shyt before modern warfare released. After that it's been like a war between the devs and the fans about the direction of the series. Bungie wanted nothing to do with the shyt, they didn't wanna keep making the same game forever so the left. 343 has been trying to modernize the series but they get shytted on for every little change they make so they try to keep it as barebones as possible.What's the fascination with this game? I played it for a bit and got a refund on Steam
The fans basically want them to recreate halo 3 with new maps, but the developers want to experiment with faster gameplay and more movement options(sprinting, dashing, grappling hooks etc.). Fans think all those changes ruin the formula because they don't wanna have to adapt and learn new gameplay strategies. It's led to the series becoming stagnant, I feel kinda sorry for 343 because they could probably make an amazing halo game if the fanbase was a bit more open to change.