I was hoping we would get a Halo 6 that would combine these two things in one game, but it looks like Halo Infinite is going with a "scrap everything, pander to nostalgia as a last resort" approach.
Nostalgia is both good and bad. Its good in that it will draw in those who fondly remember pre-Halo 4 halo, it only becomes bad when it fully relies on nostalgia and lacks any form of personality. Realistically, the new Hope trailer does rely on Nostalgia.... from an Art perspective. However, it needed too. Its goal is to get people interested who like Halo but not Modern Halo.
I think Halo 5 has some good parts (even though I don't think these parts are good for halo itself). It is a good video game, that is hard to debate. A good Halo game? not so much for me and its perfectly fine for people to like it and enjoy it.
However, that feeling you are getting now, that feeling that what you loved is being removed cause of the "pandered to group." That's what people who fell in love with the series and understand its core function have felt since reach. At the end of the Day, Halo has a look, it has a playstyle, it has a tone. Future Halo's need to understand what those are, build on them in ways they enhance the experience. Not over right it for the sake of "being a new Halo we need to look different"
This is why people make the argument Halo 4 and 5 (5 more so) is a good game, just not a Halo game.