As long as ricochet returns and has it's own playlist though,
invasion needs to make a return,
Keep Elites in ALL MP modes, not just Invasion (But still force Race for invasion mode)
And I like the idea of change to ODST/Marines in SWAT,
Your idea for Conquest sounds a lot like invasion, would be cool if it was more of a rush styled game mode though, with very large player numbers, only prob would be some maps end up being sized for 32v32 wars and not 4v4/8v8 battles, so it might work if they let high-end forgers come in early to design maps for it.