Exactly what TornandoFlame said. 343 completely smeared the skill gap and made it easier for the newcomers. I remember in halo 3 where if you didn't know what to do, more than likely it would've been an awful match for you. Not like halo 4 where you just hop right in and get going
Campaign hopes:
1. Arbiter has some sort of influence.
2. Return of the big open level layouts from previous halos
3. Having the halo 3 elites fighting back with you against the rebel storm elites and or storm covenant.
4. Make it more like the original halos in general. I kinda miss the old plasma rifle. The storm rifle is kinda funky.