That would actually be pretty neat. Would be a different take on MP side of things for the franchise, and could even be a lot of fun long as they had 20+ maps, different game modes, and so on.
Though I'd still want a 30+ hour story campaign with a deep branching narrative, permadeath of squadmates (Based on decisions you make), a combo of Isolation survival horror and shootem up when it's needed, and multiple endings depending on how you play/choices you made (Help USCM Kill the hive, bring a sample to WY, so Independant and screw both sides in some way, and so on.).
Though I know, I'm asking for way too much, that would be Old School BioWare, or Obsidian levels of Game Design. Won't happen in the current age, even though a game like that would probably break millions if made by the right team who understand what "Player Agency" and "Narrative Choice" means >.>