According to this GameSpot report Respawn Entertainment's next game will be an Xbox 720 exclusive and will be "always online." According to the report, the game will be a multiplayer-focused, always-online Xbox 720 exclusive, with a release for Xbox 360 to happen at some point but to be developed by some other studio. If the report is to be believed the new game from the former Infinity Ward developers will not be available on PlayStation and Nintendo consoles.
The game, which has not been publicly revealed yet (it will be at E3) is described as a sci-fi shooter pitting giant exoskeletons piloted by players against heavily armed foot soldiers. The report also says that the game is not being built using an EA-owned engine technology - instead it is using the latest version of Valve's Source engine.
The game may very well be revealed at Microsoft's Xbox 720 event in late May, or it will be revealed during E3 in June. Either way, it won't be much longer before we know for sure what Respawn has been working on in the last couple of years after leaving Activision.
It should also be noted that if a game has no single-player campaign and is multiplayer focused, most people won't complain about always online requirements. It's not like consumers don't know that - for example - if you don't have an internet connection, you can't Play World of Warcraft...