Hmm... haven't seen any problems not as going as a tank or a dps. also haven't heard anything from tanks in the party. The mobs already before 2.3 had the bad habit of going straight for someone else at the start even if tank pulled it - so about 1-2 second aggro lag.

Also same as before in standard dungeons - on low lvl paladin's can't hold aggro against dps. And on high dungeons - if I am OP gear wise in relation to tank i pull aggro at the start, but after that they easily overtake me. if the tank is on the same ilvl as me there is no problem.

So might be a random glitch.

Hope this won't be used as a standard reply by tanks when they lose aggro from now on