Taunting someone at max range and standing behind a tree is the most powerful card in the game. If I don't have LoS to the Taunter I should be allowed to target someone else, because omg. "Lose two turns, range 10."
The character standing behind the tree is also losing two turns of being out in the open. There are advantages and disadvantages to it. Plus, the character being taunted can still use attack cards that aren't target-based.
I've been on the recieving end of taunt. I killed the taunter. It wouldn't let me attack anyone else for 2 turns anyway because my only valid target was DEAD.
I have to say that the card should work as written or the point of using it is almost none existent since i will just get out of LoS from the taunter but retain LoS to the guy i want to attack making the card mildly annoying at best.
Just noting that killing the taunter still leaves the taunt effect on the targetted character, leaving them effectively useless for two turns. Frustrating!