This tactician we are talking about is it in-game Conan or out-of-game Kasparov player? An in-game Conan doesn't know what power the fighter is going to use next, the Kasparov might know and have been trying to get away from the fighter, but the fighter has an in-built "sticky" power. There is no way to offset a power once he is in range but hope to interrupt it or hope the fighter misses the attack.
Ok, so lets say we don't live in a player vs. character vacuum and your in game tactician actually got his tactical experience by seeing fighters actually fight. Logically that's the best way to eventually learn strategy.. be in the field, learn tactics and develop strategies...
Then your master strategist has seen fighters fight, knows what fighters do and can plan ahead when the tide of battle turns. The point of strategy is not to be in a situation where you're tactically compromised.
Thing is, it aint about the DM able to change the power based on his whim. The game has a philosophy of letting the player acquire all the powers RAW and changing a power to fit the DM's view will either hurt the balance or frustrate the player.
As a DM you can't change the power on the fly. That's something for a game table discussion before or after the game with the group. Within the game situation you have an option to do any number of things to offset the power long enough to tell a good story. Need more enemies.. there's another group of minions.. etc. Oh what's leading the minions..
Have you read what Come and Get it power does btw? The range is 15 feet radius centred from the fighter which affect all enemies around him.
Let's see it from an in-game perspective. Evil Conan and his lackeys are fighting this fighter. The fighter then shouts at them and everyone in that 15 feet radius area will immediately move towards the fighter. The moment they get close, the fighter then whacks them.
Now, if you were to roleplay Evil Conan as a guy who doesn't want to engage with this fighter but prefer to let his lackeys do the job instead, why are you suddenly moving towards this fighter?
Mechanics are dictating the npcs actions without you roleplaying it. An auto fail Will check, in 3.5 terms.
Ok, so now I'm going to get all realistic and stuff, bear with me. If I'm in a real hand to hand fight, I know that my opponent has a circle of reach equal to his full reach plus whatever I give him as his opponent. If I walk into his space, he has more he can do.
If i'm using a sword, I now extend that reach to the full distance of the arm plus his weapon, plus whatever I give him as his opponent. So the combat lives and breathes in a circle if I engage him. I want to stay at the limits of his reach if I can, therefore I'm going to move in a circle around him preferably opposite his strong side to avoid crushing strikes.
If we're using polearms, reach changes again.
So here's the deal. I'm not a military mastermind. I'm a guy who's taken some martial arts and I get it. I know that if I get in range of a guys reach and he knows how to use his weapon I'm potentially screwed. If I know what I'm talking about I may be able to tell if the guy has a particular fighting style that favors sweeps and whether or not he's fast. If that's the case I give him the respect of additional reach based on his stance and where his weight is distributed...
Back to the game. Your tactical/strategic mastermind is going to be better than I am, so he's going to know that fighters fight, he's going to know the tricks of the battlefield and how a taunt can work. He's going to know that the fighter's reach could well be 15 ft. and he's going to react accordingly... which means ranged combat against the front line and attempts to flank that front line until it's wise to close inside basic melee range, making the taunt useless. Then he's forced to mark stuff and hope for penalties if a combatant peels off.
So as to the "Hey come here" effect.. how to explain it.. I've done that previously. Maybe there's a statement about the mother's of the enemy that just annoys the enemy.. maybe there's a feud.. maybe there's a focus that makes sense.. or maybe he's just awesome and people want to kill him for honor's sake. Maybe it's a magic effect. Any way you look at it, fighters have trained themselves to know what to do to taunt things if they have the power. Hell you could say it's a result of party tactics as the power is pretty useless until you're in a group (cause if you're alone you're getting stuck just because.)
So to those who say that the tactical strategic guy shouldn't be pulled, I agree with you. I say the tactical strategist wouldn't be inside 15 ft if he was a strategist. DMs need to know their players and play the enemies appropriately. If he's pulled you failed. That's ok.
Personal note: I botch an encounter at least once a game because I don't think about something the players can do. So I'm with you, but blaming the game or the powers is just lame unless there's a real power imbalance.