I think Halo Infinite is the accumulation of a games company that has been in crisis management mode for over the past 5 years, caused by a cumulative cascade of increasingly bad story telling decisions stretching all the way back to the initial announcement of Halo 4.
I remember around the time Halo 4 was announced, 343 said this would not be a traditional trilogy but a ‘saga’ as the story they wanted to tell they did not want to limit to a 3 game arc. While I thought this was a good move initially at the time, I think now the problem is 343 set a place and a time for the Reclaimer series to start (2557, Forward Unto Dawn, Requiem), but I don’t think they ever set down in concrete time, place or event that would conclude the saga ,which meant they had no overall direction from the start. This gave 343 something of a false sense of security in that they could course correct the story as many times as they needed without having to worry about conforming to a set ending, so they didn’t reap the benefits of long term forward planning and constantly bit off more then they could chew in terms of what they intended to deliver. This led to a series underwhelming finales, flat characters, abandoned plot arcs and increasingly poor choices in terms of narrative direction to take the story in.
343 started of with a very solid location and villain for Halo 4 (Requiem & Didact) but then made the retrospectively bad decision to split their development time for single-player aspect between the main campaign and Spartan Ops because they thought that would make the game more enjoyable. As a result we ended up with a drastically shortened campaign that killed off and retired the most interesting characters and story ideas, and a weird free DLC that wasn’t terrible but few people were satisfied with, the narrative of which had to be carried by fairly flat and uninteresting characters. (Oddly enough both Jul and Palmer both fall into this category in that they were never intended to fulfil the role of complex hero and villain, but that’s what they became in Spartan Ops for good or bad)
The Janus Key wasn’t the best ending I’ve seen to the first act of a sequel story but it wasn’t the worst I’ve seen either. Unfortunately I think by that stage 343’s false sense of security was at its height and they made the fateful decision to course correct by scrapping the Janus Key arc and deciding to use Halo 5 to introduce a new set of characters, faction and story without actually considering how badly those characters and story may be received, which would turn out to exceed all expectations for the worst.
I think 343 are now at this odd cross-roads where they know people disliked Halo 5’s story so severely it stops them taking Halo 6 where they wanted to take the story at the end of that game, but at the same time they know they have to do...’something’ or else their paying for a cash cow they can’t make money off.
I think they’ve latched onto the ‘Banished’ faction as this seems to be one of the few story ideas that been universally well received by the majority of fans who played Halo Wars 2, hoping they can replicate the same success for Halo Infinite. If I had to guess, I’d imagine the ‘Created’ will be almost entirely exist off-screen for the entirety of Halo 6’s campaign with the exception of the ending, where there will be some kind of last minute power struggle (again mostly off-screen) between the ‘Created’ and Banished only for some type of Dues Ex Machina to occur which will result in the UNSC retaking control of Zeta Halo and both hostile organisations being severely weakened or else conveniently ceasing to exist. I think after that, 343 will probably look to start a new ‘adventure’ in the saga, though I’d personally prefer if they just rewound the clock back too Halo 4 and started a kind off alternative Reclaimer saga using the lessons learned to ensure they implement long term story planning with professional novelists who have actually done best selling Sci-Fi series themselves. (They certainly have the budget for this)
Maybe then we could get the Lovecraftian horror Sci-Fi opera Bungie and 343 initially intended, with the dual threat of the return of the Precursors and Flood forcing humanity and all the former Covenant species and revived Forerunners into a last ditch alliance for the fate of the galaxy.
(Though that’s unlikely as it would violate the one rule of big corporations. Never acknowledge you’ve made a mistake, even when you have)
It's just wildly un professional to not at least give a bad reason (halo 4 chief armor style change type explanation) than no reason at all as to why the story changed like it did.
Slightly disagree with you here as far as visual changes to armour, weapons and vehicles go. This all comes under artistic licence which will change from game to game anyway, sometimes the worst but mostly for the better. As long as the gameplay and story is good, reasonable suspension of disbelief should mitigate any issues with what people see.
What annoys me is when 343 try to explain away Artistic licences changes with rushed explanation that hamper or outright contradict the lore. The nanite tech in the MJOLNIR is a prime example of this. Not every change in Artistic licence needs a reason to explain it.