Blizzard
Specific questions are generally easier for us to answer than broad "please talk about <insert topic>"-style posts, but this one actually gives a good opportunity to share some of our general thoughts about PvP at the moment.
Regarding overall class balance: in Arenas, we're overall pretty happy with it at the moment. We've been hearing a lot about the prevalence of Rogue/Mage comps lately, and may end up making some changes, but we're more likely to focus on buffing some underperformers than specifically nerfing anyone right now. To put it another way: Rogue/Mage is (and should continue to be) a strong comp, we just want to make sure there's a good number of other strong comps as well.
We made some changes not long ago to Random BG matchmaking to help with healer balance, and have been very happy with the initial results. There's still some edge cases we're looking to iron out (specifically, we're sometimes seeing games where one team has 2 healers and the other has none), and so we're still working on some additional improvements. So far, though, there's been a very noticeable difference overall.
Lastly I'll mention that we're planning another PvP-focused Live Dev Q&A, probably sometime around early to mid March. We'll get a proper announcement out once we've finalized all the details.
Blizzard
Personally i would like it if they would upgrade the drop chance on the friggin essences from EN
Swithed character in november (was a feral druid and the RSI just wasnt worth the output) But now ive had 2 essences drop per full EN heroic clear. Just make it 100% from EN heroic that way even alts can speed it up a tiny bit.