I would explode with happiness if it was like Call of Duty,where you periodically changed what soldier(and what kind of) you played as.For instance,you'd start as an elite,2 levels,brute,1,grunt(Which would be like a stealth mission,playing as a spec ops grunt,as the others would be way too weak) for 1-2,then maybe a jack or hunter(O_O),and change back to the others until the squads eventually meet up on one of the halos,or earth,or wherever it is for the timeline.