Halo doesn't need budget, it needs vision. Everyone at 343 was hired intentionally to have no vision of what halo is. Look at the old interviews of 4, and they all say as much, they hired cod fans to make a halo game. And look even at the story, they completely misunderstood that the forerunners ARE human. The misunderstood master cheif and cortona. They hired people who knew nothing about halo, and expected them to make a good halo game.
Id be more then okay to never see them make another halo game at this point. 3 terrible main line games is just too much.
They need people who understand the gameplay loop and story of the original games. As well as a huge focus on forge imo, i didn't care much for forge, but it was a huge part of what kept a large portion of players playing 3 and reach. So good campaign, split screen, forge, firefight, ALL at launch, it honestly isn't that hard, but it's impossible for 343i