It's no more powerful than t4 pve gear, the only stat missing from the t4 gear is tenacity, which might make a difference but seeing as tenacity was added to all pvp gear as long as your using pvp gear of any level there is only a minor change from t1-t3 pvp gear for tenacity. The critigation is a big leap from t1-t3 pvp, but for the most part all of the sets offer more tenacity than critigation so your at a disadvantage using pve gear concerning tenacity.
PvE gear still offers more damage, critical rating, and critical damage rating albeit not much from the t3 pvp armor sets, except for soldiers where they tried to balance their critical rating to less than every class. The critigation is about equal, the only major difference is protection and tenacity if you compare the t3 pvp armor sets and the t4 pve sets.
I don't get where your seeing that t3 pvp armor is too powerful when it's not very different from t4 pve gear, where no one had to pvp to get any of it and most of it is free as drops. I can't see why anyone would want to go back to pve armor being the best for pvp, IMO even t1 pvp armor should be better than t4 or any pve armor that someone got without ever having to kill a single person or win 1 mini.