I personally feel that Far Cry 2 would have benefited more from prone than lean.
I think it would have greatly benefit from both.
I think we simply have different criteria as to what makes an immersive game.
Seems like it.
Not to refute it but I speak to developers with my wallet.
As do I by buying the games I like.
It felt fresh, from the movement, to the combat, to the environment, to the way you had to heal yourself. It was about how it all worked together, rather than any one feature.
I thought the combat was solid and the ambience was good but aside from that, nothing really stood out to me as pushing the genre forward. They had a lot of great ideas but those ideas either didn't make it into the game or were executed poorly. Hopefully Far Cry 3 can live up to its potential.