What is quite funny ...
The mechanic you are talking about is allready implemented ... since when you have some conversation tied to Tav, game will cancel his animal form, conversation will happen, and then return him to animal form FOR FREE!
Im not sure if i remember any example corectly ...
But i believe, that when you kill those Goblins at Windmill, Wyll wants to talk with you imediatly after the fight ... unless i remember it incorectly, that was when this happened to me.
So, once game will automaticly choose Tav for conversations, instead of "the nearest PC" ... problem should be solved.
