Since "silence" is one of the shortest duration skill of entire game (1sec min - 3sec max, which only can silence "spells" type of skills but doesn't not stop any of abilities at all! In PVP "silence" pretty much was nothing but useless skill since every classes don't have so much time casting spells when running so they prefer using abilities to heal themself and many other stuff they can still do while silenced. If you silence a summoner, he can still use its abilities to damage you, since when did summoners don't use their abilities instead of standing there casting spells? Not what I know after 3.0 patch...
I will like to see silence will actually "silence" abilities as well in PVP in the future. It will totally not gonna unbalance the game, since it's only 1sec normally uses or make silence duration longer will be great as well.