We had the taunt/stealth fix where if a toon has stealth and taunts, it dispels stealth for the duration of the taunt.
for the p4 traya issue, why not just have the same concept apply. For the turn that a character taunts using the raid buff, the character cannot have the actual taunt buff. once the raid buff expires, the taunt returns (unless it was set to expire 1 turn later as well)
another idea that could have been implemented that would have been much better than stacking infinite tenacity, and would fix the p3 traya issue, is that Raid bosses in the sith raid no longer have ridiculous tenacity, but every time a debuff or turn meter reduction is applied, the next time it is used it is 20% less effective until the raid boss' next turn.
Ex: teebo reduces 100% tm on his basic, then 80%, etc. If another character uses tm reduction it still is reduced in efficiency based on how many times tm has been reduced on the boss that turn. so if the 3rd reduction is han solo, if it lands then the reduction would be (.6 * 35%) and (.4 * 35%)