Why kill the Wizard if the Fighter deals similar amount of damage per round, and stands in front of you?And if he can take an AoO if you try to get past him? How do you even get to the stupid wizard that likes flying around, outside your reach? And what do you do after you killed the Wizard? Do you think the Fighter will just go home disappointed? Okay, if you want to give up your lair, fine... But then why don't you just run?
Why should a monster bother to kill a lightly amored fighter this deals little damage and is running away from you all the time? Why not just jump a more "squishy" target that is actually a threat? Maybe it's really worth trying to jump up to that nasty Wizard and catch him?
The best solution off course is to deal massive amounts of damage, being fast, and being hard to hit at the same time, but that's hardly achievable in 3E. Speed for a Fighter is only useful for catching up to an opponent, not for moving away from him (unless he's retreating). If he is not near his opponent, the opponent has the best chances to pick targets as he likes it, which is probably what you don't like.
That off course is only true if you're using a Fighter in a Defender role. That's very often expected, but not a given, in 3E.