Assassins Creed 2 to be longer, just because it was an enjoyable experience. I wish there was more built into Kane And Lynch: Dead Men's Fragile Alliance mode. There's just so many places you could take that mode like a reputation meter, levelling up, additional guns, modifications to said guns, longer levels instead of repeating said level three times so it's more like an actual job and multiple ways to complete a level (e.g. you COULD get into the van, or you could make your way through a shopping centre to get away or you could rob a car and make you way out of there, as long you get to a check point, like Reservoir Dogs).
To be honest, Fragile Alliance had such an original and psychologically amazing base, it's just so easy to make it a fantastic game.
Edit: Which by fantastic game, I mean at least make the Kane And Lynch: Dead Men memorable in a lot of people's mind as an astounding game, one with an on-line mode people keeping going back to; or you could make Fragile Alliance it's own game with enough work, just because it holds so much potential.