I enjoyed Far Cry 2 for a while, but never finished it and lost all interest after a a few days of playing. The rate at which enemies respawn, combined with the need to traverse huge areas filled with said enemies, ruined the experience for me. While the combat was fine, even thrilling, having to constantly engage in it with profoundly poor AI, whom you had already killed not ten minutes ago, became frustrating.
If Far Cry 3 can carry over some of the elements from 2, it could be great. The jamming weapons and first aid in the middle of fire fights reinvigorated a time worn gaming mechanic. The simple, fairly realistic weapons, felt and handled how they looked and that was somehow cool. The environment looked beautiful and the fire mechanic--as limited as it was in hindsight--made for some "oh, wow" moments.
It's a shame so many little things hampered my enjoyment of Far Cry 2 as much as they did, considering how great a lot of the game was. I hope the team learns from their mistakes and serves up an incredible game. I think they can.