To get back to the topic at hand:
As a Halo fanboy for over 20 years who's put 2500+ hours into the combo of Halo MCC and Halo 5 and about 15 hours into the tech preview, this Halo has its best foundation. If it didn't, I'd be screaming from the rooftops to delay. Best combo of movement and gun play. Best potential addition to the sandbox since the BR with the Grapple Shot. The bot AI is the best AI I've seen in a Halo. The foundation and sandbox for that 30 seconds of fun gameplay loop will be there in its widest and most vertical campaign environments. They have the absolute most important thing nailed with the gameplay.
The engine went through its most significant overhaul to allow content to be created faster for single and multiplayer, have a more complex level creator in Forge and more advanced AI. It's a platform. Not a game. There will be a lot more content that releases for Infinite after its official launch date over the years which is why the core gameplay is far and away the most important thing.
Infinite is running behind and development has been rocky. It very likely would've been delayed even if covid never happened. For point of reference, Halo 2 had a 1/3rd of its campaign cut. Halo CE had the entire campaign rebooted in the final year of development. After 5 years and only having to focus on a campaign, God of War 2018 was in bad shape according to Yoshida himself only 6 months prior to its scheduled launch. Welcome to the world of AAA development.
Most Xbox fans who've been furious about this are more concerned about narratives than the game. 15% of everyone who played Halo 5 beat a single level in co-op on Heroic. The numbers aren't significantly higher between normal and Heroic achievements. That's not 15% of people who value playing Halo in co-op first. That's a single level at any time ever. Stop worrying about "narratives" and play games instead. Let Microsoft's marketing team deal with the narratives. If you know Halo and played the tech preview, you know there's a lot to be excited about with the upcoming Halo platform.