My favourite Halo is Halo reach :).
The challenges were one of the biggest reasons, it made me keep playing the game.
The campaign challenges were great and a missed oppurtunity for Halo Infinite, it would increase sales for the campaign + have a bigger active community.
So many times I came home and people were inviting me for a party so we could do a LASO challenge campain together and we would spend hours trying to get it.
Always dissapointed that I never reached max rank, I had 2000 campaign levels completed, 8000 MP machtes played and 6000 firefight/Scoreattack matches completed but still Need to play like 30% more.
Always hated when Halo Reach joined MCC and their is no rank anymore, and matches played said 0. Still that day on release people messaged me to play some challenges after like 10 fecking years...
Gears 4 was my least favourite Main Gears game, the linear path really felt like the reason. The game needed some new ideas.....
Gears 5 tried the open world stuff, it was certainly different but at best it was a step in a good direction....
The thing is I want the next Gears to be linear but with some refreshing ideas....but maybe have like some kind of extra open world MP mode , an open world map with your own created Gear that gets updated and you can play like Escape/Horde type of events on it that unlocks stuff for your character(skins example) that you can also use in the MP. An hub with Khimera's or KR's waiting to pick up a squad and bring them to a certain event sounds great. (Thins as 'Lead an spotted to point A that's a trap but halfway in the missoin you find out their is not just one but fecking four of them...)