I'm really looking forward to Far Cry 3. The graphics do look gorgeous and the environment returns to a tropical island. BUT, If you really want to compare Crysis 3 and Far Cry 3, well....
Far Cry 3 has multiple open tropical islands to explore. Vehicles, Sandbox Gameplay, Crazy villains, Drug-trips, Man eating tigers and animals, beautiful scenery, Hang gliding, It also has a bow as a weapon
So, except for the nanosuit, Far Cry 3 looks more like a true successor to Crysis 1 than Crysis 3
But really Crysis is it's own beast just coz of the nanosuit even though they kinda nerfed it in C2.