I was playing through Sniper Elite 4 again recently and it's definitely the best one yet, especially with the co-op, but I'm perhaps getting a little WW2 thematic fatigue with it. Rebellion also have a ton of 2000ad properties, why not mash them up?
Stealth some Dredd into the global consumer's diet for example. Sniper Elite: Cursed Earth, a game where you play an SJS Judge ordered off into the cursed earth to take down the leader and top brass of a rapidly growing insurgent mutant army that has taken over a load of townships and will soon be knocking on the walls of MC1. Rumour has it the leader of the army is a Judge that took the long walk 20 years ago.. If possible it could continue the Sniper Elite trend of opening up and go fully open world, with a big desert littered with occupied villages and townships that you can attack from any angle.
Awful, murderous, rapey mutants will make quality x-ray fodder in lieu of Nazis, and it would be extra fun to line up a 3-in-1 headshot on a mutant with three heads or just getting to see all the weird insides of different kinds of mutants. Does he have a brain in his bum? It might not always be obvious the best way to kill one, especially the more powerful mutants!!
The other thing I was thinking about - if Rebellion havent had their arm bitten off yet behind the scenes by a big rich developer wanting to make the open world Mega City One Dredd game we all want, have they considered offering it to Microsoft? With Sony making Spiderman exclusive to PS4 and MS absolutely crying out for new exclusives of their own, that could be a great way way to get the funding a Dredd game deserves!