I really enjoyed Deus Ex, but the shooting mechanics were not good. I went total stealth in that game mainly because of that one aspect.
Did you play the first Crysis with any graphics mods installed? I replayed it earlier this year with Realmod (I think that was it), and I still think it makes that game look better than any current game.
Also, if you liked the Crysis games, you may want to check out Far Cry 3. I've been playing it since yesterday, and I'm very impressed so far. Far Cry 1 and 2 I thought were pretty meh, but 3 is good. It doesn't have lean, but it implements an auto lean system of sorts, when you're at the edge of cover, aiming your weapon will make you poke out to the side, or up and above cover.
On the hardest difficulty, it makes you play very tactical as well, and the gun mechanics are very solid.