The AAA game industry loves to chase trends, but if there is one trend I'd like for them to chase it would "returning to the roots." Trend-chasing has resulted in too many games being all same-y. Last gen it was going after the whole gritty "realistic" modern-day/near-future shooter with loadouts in the multiplayer mode. This generation it was enhanced mobility and, more recently, battle royal modes. In the mid 90s it was gory fighting games attempting to capitalize on Mortal Kombat's success. While there is nothing inherently wrong with adding or changing things inspired by other games, far too often it results in more homogenized game design within genres.
And Halo wasn't spared from this trend-chasing. While the original game was a pioneer that either introduced or popularized things that are now standard in the genre—the guns/grenades/melee triad, twin stick controls, the two weapon limit, level designs that weren't all claustrophobic corridor crawls—recent games in the series have instead leaned more towards being imitators instead of letting the series keep doing its own thing.
Reach and especially Halo 4 were COD-ified Halo, which eschewed the level playing field of the first three games in favor of an unbalanced loadout system. While Halo 5 returned things to a level playing field, it went full-bore with enhanced mobility, which was all the rage at the time, ditching the slow, methodical pace of the original in favor of a twitchy fast-paced experience that had profound effects on map design and the flow of combat. Even Reach and Halo 4 experimented with enhanced mobility with sprint and jetpacks.
I'm all for Halo continuing to evolve its combat, but not in ways that move it too far away from the fundamentals that made the older games so unique. The scale of Halo CE made it really stand out at the time, so maybe future games ought to focus on those sorts of massive, awe-inspiring environments and diverse, large-scale encounters (maybe not outright open-world, but definitely levels that actually do surpass Assault on the Control Room in terms of playable area traversable not just by vehicle, but on foot if the player so chooses). Perhaps Warzone can be expanded upon similarly, by making it a truly large-scale multiplayer experience, like a 16v16 or even 24v24 mode with a wider variety of subtypes on maps that actually do have several times the playable area of Blood Gulch. Maybe more interactive environments like the kind we saw in Halo 2 and Halo 2 Anniversary multiplayer could be added. But the pacing and balance of Halo's combat should remain more or less what it was in the original trilogy, with a level playing field and a slower, more deliberate pace. Halo 2 Anniversary took that old-school gameplay and polished it, and as a result it created what I felt was the best-playing Halo multiplayer mode to date.
I really hope Halo Infinite is a return to form for the series. I love Halo, and it's about the only thing I play online for the multiplayer, but under 343 Industry's watch the series feels less and less like Halo in terms of gameplay and aesthetics. Well, the latter seems to be going more classic in style, so hopefully it's the case for the former as well.