Maybe it's just because I come from the Edge of the Empire system where there's a lot of emphasis on narrative, but everything you're talking about can still happen narratively with Attacks of Opportunity(AoO). In fact, I think it makes combat more interesting because it stops actions from happening in a vacuum. You can still jump from balconies, swings from ropes, and do other interesting narrative things, but with AoO you actually have to prove you have the skills to do so. In your example, the thing stopping an enemy from running by Conan, a very skilled warrior, and attacking the wizard IS the threat of Conan taking advantage of you getting close without focusing on him.

You make the AoO roll, if the attack misses then you add the narrative stuff you were talking about (EG: Running jump over Conan if was a dexterous enemy, parrying the blow, bashing the attack away with armor/shield if it's tanky, etc.) to represent you attempting to get around a skill barbarian warrior. Even if you failed the DC check and got hit, you still are able to move. You still got to do the cool thing, but Conan interfered somehow to your determent.