I loved the first Far Cry. Besides the great graphics and gameplay, it had the best editor ever - blows away any Quake/Doom/UT editor ever released.
Real time terrain manipulation and deformation 'in the map', not in some third party program you had to import and then tweak. Real time vegetation placement with lighting and movement, no static object that isn't rendered until you play the map. Real time terrain painting, and a full featured auto-paint based on height/slope/whatever. And AFAIK, the first real use of physics in a meaningful way (again in real time).
The first time I connected a chain from a powerboat to a hang glider, put a driver into the boat and spawned myself in the glider - joy. It didn't work perfectly, but it did work. All done in about 5 minutes; the editor was awesome.
Far Cry 2 was just too easy; making you like a superhero instead of a mercenary. I enjoyed the super speed and being able to switch up on the fly, but even on hard it was very easy. I never had those multiple deaths where I'd replay a part and even enjoy doing that (car driving in FC1).
For the third, I'll wait for a demo. The multiplayer was never good in any Far Cry; decent, but not really good, and this new setup sounds gimmicky...