Having played The Lord of the Rings Card game over the weekend, it would be great to apply the same formula to Warhammer 40K. The idea of a co-operative quest game using cards works really well and, once they have ironed out the flaws, could be used for future games. Having the Deathwatch setting in the Jericho reach would be good for a living card game. Quests could be missions and the characters could create their mini-kill teams to progress through the environment. I know that Death Angel is out, but using the LOTR template would be great. Hopefully Elder sign will be a success and pave the way for future games.
In addition, the new gears of war game looks promising. Allowing that to be applied to Warhammer 40K could be a good idea. A tactical game where a squad of marines need to work together to maximize their abilities would be a good way to simulate the squad rules in Deathwatch.