This is the Unfortunate Consequence of Sequelitis… Ideas and implementations are finite, and even IF you could come up with an idea or three to implement into the newest sequel, most devs usually never seem to ask themselves if they really should…
On one Extreme you get EA’s FIFA and Madden Series which are literal copy pastes every single year (which people still spend money on by the way…), and on the other extreme, you get something like this. Games which try to change what made the original great, for every single iteration. Sometimes it works (like with DOOM Eternal), and sometimes it just goes up in smoke (Halo 5 Guardian’s Campaign and to some, the MP too)…
The issue with the latter is that it takes more work, more resources AND is a HUGE gamble, which is why most publishers will do so with existing IPs rather than make one from the ground up, so as to increase sales at the very least… Anyone who genuinely believes a sequel to a game can be made yearly from the ground up with brand new features and gameplay is beyond deluded and honestly irrationally unreasonable…
I still remember when Capcom tried to finally make Monster Hunter different with World, their very first game where they’d be doing everything from the ground up, including many of the mechanics, animations, and models. While the game was very much well received, the launch was fairly disastrous, it was barebones content wise, fairly buggy and very poorly optimized on PC (even ran kinda crap on console tbh…). Took em years before the game was finally content complete and fairly bug and crash free, there was even a drought of content at first…
What I am saying is, this is probably just as much the fault of those who continue to expect 343i and Microsoft to continue to reinvent the wheel instead of simply giving people what they want… we cannot really expect anything less than the bare minimum to be done when people want everything and they want new and fresh right away…
As much as I love Halo, I’d rather them make one last great game and just leave it at that, rather than continue to butcher the series with sequels, ala CoD or other Sequelitis plagued series on the planet. All good things must come to an end at some point. Maybe the fresh coat of Paint Halo needs IS to be put on ice for a bit…