Sorry but, bullshit. Prot PvP is not about survivability, saying that only shows that you have no clue. In fact you take bigger crits than Arms because you sail at 550 resilience (ish) when Arms should be at 900. When your CD are in cooldowns you can be despawn very fast. But you are not in the Arena to be focused and, in fact, an ennemy team focusing a prot warrior in an arena is really stupid. So your argument is invalid. And I dont understand your last sentence :/ what are you trying to say ? lol.
Prot PvP is a mix of utility and control with decent burst. Check my spec (Armory is in my sig), 12/8/51. Basically, you need two T10 tanking pieces (for the bonus), a couple of PvP gear for some resil and some crit (i got the trinket, and relentless head and shoulder), a slow weapon (2.60) for big Devastates, some block value (BQL shield is nice, ToC 25 Beasts is good too, and Valithria gun) and then, PvE dps gear. Full ArP. I'll try to log out in my Arena gear tonight so you can check it out. Currently i'm rocking 550 resilience, 750 Arpen, 35% crit or so, 2000 block value and I cant remember my AP, but it's decent too. Right now i'm only aiming for more resilience (Relentless => Wrathfull) and an Arp Trinket (hello Halion).
Prot PvP isnt made for all comps. Basically, you need some form of MS with you, 3v3 is where we shine. Play with an Arms warrior and a Palaheal, which i am, and you're playing Mancleave, which is TONS of fun. Play with a Hunter and a Palaheal, and you're playing African Turtle Cleave, which is fun too. Dont go 2v2 as Prot, you will fail. Not enough burst. I dont know about 5v5 but it would probably fail too. Prot PvP isnt flexible when you want to build a team, you cant play with all class / spec sadly. That's what Arms is for =)
As prot PvP you can fulfill many roles.
1. Stick on this caster's ass and CC him, Reflect him, stun him, take him low-life slowly. He cant damage you, but you damage him a lot. It will require some heal on him so you're giving your DPS partner some breath to DPS his target. Pay attention when he casts some CC (sheep, hex, cyclone..) and try to reflect these.
2. Full interrupt on the healer in a burst phase. If you're good you can prevent every cast and dispell hots. You will also deal a good chunk of damage on the healer
3. Turtle mode on your healer / dps if they're getting focus badly. Intervene (safeguard specced). Disarm melees. Fear. Shockwave the DPS. Spell reflect (specced). You can prevent a huge amount of incoming damage.
4. Pure DPS. Here you are on the same target than your dps mate. Shield Slam, Conc bloc, Shield bash to daze him, stunlock with Charge / Intercept, Devastate, Disarm (specced for extra damage).
This spec not dead. It's far from ideal and it probably wont get you to gladiator, but it is really fun, and it's VERY viable up to 2k. I'm not gonna link Xanadu's armory AGAIN because it's getting old. But check this video guys. You'll enjoy it.
http://www.warcraftmovies.com/movieview.php?id=149191
Edit : oh and, in BG : Prot > all. As simple as that.