Confession: I am a massive Halo fan
....well, I am a massive Halo Combat Evolved (Halo CE/Halo 1) fan - I played it endlessly back in the day and still occasionally dip my toe in.
Halo 2 was pretty abysmal - the whole dual-wielding of weapons and playing great chunks as The Arbiter detracted from what otherwise would have been a good game (my personal opinion).
Halo 3 went some way to fix it but also by then the wholeadd-ons and gadgets thing had crept in and it became ever more difficult to master multiplayer.
Halo 4 and 5 were ok. But another thing that let it down for me, personally, was that 3, 4 and 5 were console only. Which was a shame.
"...Fortunately, one does not have to be a Halo lore boffin to appreciate the direction in which 343 has taken the series, and I have a sneaking suspicion that many long-term fans may hold Infinite as a return to form. The gameplay feels more like Bungie's Halo 3, widely regarded as the franchise's peak,.."
Personally Halo CE was the franchise's peak for many players. Halo 3 was more of a return to form, but Infinite is the most Halo CE of the sequels yet, in my humble opinion. The pace, the weapons all feel very much CE. Even the grappling hook adds to the feel rather than detracting from it.
I've played the campaign through and thoroughly enjoyed it but it does feel very unbalanced in places. Some bosses fold super easily. Others just pummel you into the ground time and time and time again until you catch a lucky break.
As successors go, I'd rank it very highly. If you're a fan of the original you're in for a treat.