Do you see it necessary to put back ranks?
Honestly no, reach is more social, and return to make 20,000,000 million for inheritor, no thanks.
It would be nice to have a ranking system though. I find myself getting bored and having a difficult time finding something to do (especially if you've already beat all the campaigns) but I feel like having to rank up my character or profile would fill that Gap and give a little more to multiplayer
necessary? no

do i want it anyway? yes
They did announce an new progression system similar to reach ( for unlocking these armors for example ) could guess it would be a copy of that ( i mean many asked for this for a long time like an xp system etc )
I would like some kind of new ranking system. Reach introduced the daily and weekly challenges which I loved. I hope it has those plus ranking. A combination of skill-based rank and XP rank would be cool. Just don't make us play the old Arena gametypes.
Hopefully the "new" progression system is just that and the skill system will stay in place as it is. Progression from simply playing much like Reach was while continuing skill ranks in competitive.
If the ranks just serves as a badge to remind players how much this guy has played, I wouldn't even consider the Halo Reach style ranks to be a necessary addition to the collection. Unless they make those ranks tie in with the EXP system like in Halo 3 (if they plan to implement that is), maybe I'd say it's a fine addition to the game.
I just want them to have the same system as old reach and idc if the ranks would be reset because that would give me another reason to be on it all the time
I honestly hope for a global rank system which is similar to reach and a competitive ranking system for competitive like the current one they have on Halo 5 and Halo Wars 2.