About midway through the General section of the PTR Patch Notes, you'll find that "Silence and Interrupt effects now have diminishing returns when used on PvP targets." And while this has many classes up in arms, it has me saying "it's about time!" Sure, a Warlock's Fel Hunter and Spell Lock will be affected by the changes being implemented, but I'm not too worried about that. An astute Warlock doesn't spam the ability or have it on "Auto" anyway, but instead uses it conservatively and carefully in any PvP environment. That's especially so in Arena play. So really, the impact on the 'lock is minimal from that standpoint.
From the opposite end of the spectrum, however, it's a different story. Where the changes really come into play are with abilities such as Earth Shock, Improved Shield Bash, and the like, all of which are on short cooldowns and can be spammed accordingly (drain-tanking Warlocks know that all too well). And while this created more of a nuisance than a real problem, I often felt that the mechanics were a bit slanted.
With all of the nerfs that have been applied to the duration and return of CCs such as Fear and Polymorph, I often wondered why Silence and Interrupt effects weren't thrown into the mix. They are a form of control themselves, after all, so it makes complete sense that they are given the nerfed PvP treatment, no matter what some have to say. So it's good to see it finally happen.
In actual play, the changes are noticeable, at least when giving them an extreme amount of attention. In 5v5 Arena, keeping the healers in check proved to be a bit more difficult and doing it well and effectively emphasized coordination and planning between different types of CC. In other situations, the changes were still obvious, but a little less pronounced.
One thing is for sure: in PvP play, finesse is becoming more and more important than than basic brute force (unless you have a Warrior, like Kalgan does). Given the list of changes over the past many patches, it's a safe bet that this is the case, that the trend will continue, and that players will just have to adapt to the new "style" if they are to remain successful.
It'll definitely be interesting to see how these changes sum up and affect the Arena scheme of things, and PvP in 2.3 in general.