Lets look at the simplest problem you brought up first, no tells in dungeons/instances. For the sake of argument lets say there isn't a restriction from coding side of things, and this was a developer decision due to harassment concerns. One side will claim people are less likely to be harassed due to you would have perform threw means of party chat. While others believe this harassment intensifies threw mob mentally in party chat; that others will likely join in to harass the said person in question. Yet another side of the community believes the others now being aware of the harassment will come to the aid of the harassed player and vote kick the one harassing.