The stance of "Halo was always designed this way, so it should remain like that" doesn't really make much sense because there have been rather drastic changes between each Halo game (sprint, dual weapons, equipment, armor abilities, spartan abilities, loadouts, REQ's, perks, ADS, different jump heights, walk speeds, etc.). I don't think removing or altering the radar would have much of an impact in the grand scheme of things; I think it would help the meta game. The other things you're arguing, like saying how Spartan Charge would be useless, I think those in favor of radar would actually argue the opposite, how no radar would make Spartan Charge more prevalent, a concern I agree with. Again, fair compromise = sound/spartan ability-based radar.
And you know damn well you'd still play Halo if they removed radar. Halo 5's gameplay is too good.. What would you do, go back to TMCC Halo 4? lol