Gear in PVP matters, but relative to how much it matters in other pvp games it's actually a fairly mild curve. I'd rather have 0 expertise in TOR than 0 resilience in WoW to say the least. And they've made gearing up really quite easy with the ability to earn 20 champion bags in a week with just dailies and weeklies, not to mention the bags you can then buy while doing those same quests. Plus, PVE geared characters are far more viable in PVP than they are (or at least were, I'm out of the loop) in WoW so you can take either avenue.
Respecs can get steep pretty fast if you do it often enough, my friend had them up to 100k the other day and I hit 50000ish last night after what felt like not many respecs. Though supposedly they reset every week or give you a free one every week or something, I'll find out on Tuesday. I do hope they add a dual spec of some sort in the future, at least as a healing sorc my PVP and PVE specs don't overlap much.
And this weekend my friends and I finally got ourselves into some OPs and were really impressed. We had a legitimately awesome time and managed 5/5 EV on Saturday and 4/5 KP yesterday until we ran out of time last night. After years of WoW and other games in between the bosses still felt fresh. The trash wasn't too extensive either, but every now and then it still caught us off guard. Also the amount of 'running back' is limited, when you wipe you can get back on the horse fairly quickly. It actually made me want to try some of the flashpoints as well since I only ever saw two of them while levelling.
There's plenty to do at 50 so far imo, probably just not if you only want to do 'one thing' (story, pvp, raid, craft, quest, grind, etc). But to me those systems are all developed enough that if you split time between a few of them you should be able to keep 'busy' as it were.