Halo 5 Wants:
1. Spectator mode for sure, as someone already mentioned. A must have for games that want to be taken seriously as competitive e-sports games.
2. Bring back dual-wielding.
3. Remain true to Halo's colourful acrade-style look. I don't want it to go for ultra-realism like BF4 or CoD.
4. Bigger multiplayer game modes, as long as it doesn't create lag.
5. Increased amount of enemy types for single player to keep it feeling fresh all the way through the campaign.