Yeah, I love the look of Halos 4&5 but they are all arenas with (as DF calls them) 'baked-in' lighting effects. As Richard says in the first vid they did, the non-stream version they got in the press kit version MS released following the conference looks a LOT better.
My guess is Slipspace was developed from scratch to work on the original Bone, allowing for lighting effects to be overlaid. Problem is, looks to me like a) lighting effects aren't ready (doesn't even necessarily need to be ray traced, could be anything - none ready) and b) they've fucked-up with LOD and pop-in big time. I'm not sure how big a deal or how long it'll take to fix but there are only two things that can happen here...
Either they pull it from release and give themselves at least six months from the proposed release date to fix this -- so well into Q2 2021 -- or they release it anyway with patches forthcoming. They might be able to get away with the latter as it's primarily going to be played on Game Pass, let's be straight here, but it'd be a baaaaad look from a marketing perspective. But if they miss day and date with Series X release, it'll really harm them.
The worst thing in all this is, it's hitting all the problems both Destiny and Anthem had, but this is worse as not only should 343i have learned from those lessons, but it's also the flagship release for a new console!