Well, being originally a simulator-freak (now more a strategy gamer), I can only say that better 3-D graphics, sound, etc, have done wonders for the simulator games.
I'm still playing
Ghost Recon and it's an awesome simulation. It doesn't even feel like a game sometimes, though I understand some people will find the politics not sound. Anyway, after some patches the enemy AI is even better and now I have big problems keeping my team alive in some missions.
Like this mission where you have to support a tank team, capture a town and destroy artillery on hill tops. Just now I completed the mission again, best result so far: only two of my team killed. The tank was destroyed unfortunately, as was most of the tank infantry. But 4 others of my team made it and we got those artillery pieces...
I wouldn't recommend playing this game for prolonged sessions, but for a quick shoot (15-25 minutes) it's superb. A real thinking, tactical shooter this one.
CIV II had one big mistake: you could use cannon to attack (it's only a support unit) and if the enemy had railroad tracks you could almost play like you were using tanks instead in a blitzkrieg campaign. I also think the 'Culture' factor in
CIV III adds much to realism and captured cities revolting is a nightmare but look at reality. It's not that easy to capture and hold territory (with people on it).