For Halo 5, how about an environment that Interacts with players and the map itself?
Maybe for a map say...in the sand dunes in the middle of a dessert...there's earthquakes and strong wind that cause dust storms and maybe a warning signal telling the characters to find shelter or something...because it takes down their shields and stuff.
Maybe for a jungle map or something you can shoot down a tree to fall on an enemy...or maybe have actually animals in maps that will fight against players.
It'd be a really neat idea don't you think? It'll really meld with the whole "going for a futuristic/realistic feel" for next-gen gaming. Having the environment dictate some of your movements.
Just a thought, let me know what you guys think