While yes, you can trinket a silence..you may want to save it for one of the many CC's/stuns available in today's game. If necessary I don't think making casters actually cast more again is a bad thing so interrupts are worthwhile again, just adjust them a bit to compensate.
I was doing 2's with a Frost Mage earlier today for points and it was incredible how could completely lock down a healer between polymorph/deep freeze/impact plus not even needing to hard interrupt a cast but just CSing for the 4 second blanket silence when their partner was low. Throw in Repentance and HoJ and it was pretty stupid.
On the flip side too, playing against that is pretty much a !@#$ing nightmare...especially as a caster melee spec(Ret Paladin/DK/Enhancement Shaman/Feral to a certain extent?) since you're unable to do much of anything while silenced.