I always had a tough time playing a warlock; the playstyle never really appealed to me. The closest I got to having fun with it was when they changed destruction to be a bit more like a mage; ie, lots of bursty shit that proc'd etc. Destruction might still be that way now, but apparently it's also the spec with the least dps so that's a bit of a turn off.
Demonology is a lot more fun, although it seems a bit tricky to play it perfectly; you're not just prioritizing spells, but you're also maximizing uptime of demon form, including when to cancel it, when to turn it on etc. Felguard is still a beastly pet though. I took soul link on my warlock as the third(?) teir talent, and with soul leech, siphon life + healthstones and drain life, it keeps my pet and I at full health most of the time.
As far as PVP, as a druid restoration used to get consistently hit with the bat because of pvp so I feel your pain. Original EQ established separate rulesets at some point, and it seemed to easily flow into the game so I am really uncertain why they are dragging their feet on that shit. No one likes sledgehammer solutions brought in during a quick hotfix, especially ones that change your playstyle, require you to regear, reforge, retalent, respec etc, but that seems to be how they do things.
One of my biggest pet peeves is having to relearn my damn class every expansion, and christ, playing alts is mind numbing. I log onto some of them and half of my abilities are gone, things work differently, ugh. Every patch bringing with it more changes to how they want the class to function is ri-god-damn-diculous, especially since I don't pvp often. So my raid will see a decrease in power (though mages were probably a bit out of whack, but who cares really in pve) to compensate for pvp that most of us will never benefit from. It's wearing.
On the upside, I was catching up on some reading and finally bit the bullet and farmed out the rest of my rares for the Relic Hunter title. Nice to have that out of the way.