I believe that the UNSC Infinity is going to be a kind of Spartan training center, built solely after the war to train the new generation Spartans. The terrain generating capabilities of the ship give it excellent potential as a training center and I think the multiplayer will be based on completing ‘training missions’ against other spartans who are in training on the ship. Sort of like a simulator. I think this would provide great opportunity for objective-based game types and Invasion games. As your spartan completes parts of his/her training, they get something similar to the previous ‘commendations’ that are like awards for progress in certain aspects of training.
Respawning would finally make sense 
Spartans fighting each other would also finally make sense
What do you guys think? It’s seems pretty likely that the multilayer will be something along these lines but what are you hoping for as far as the context of the multiplayer goes? Do you like the idea of spartan training as a multiplayer mode, or would you prefer the usual - Real battles between spartans on different teams for no apparent reason?