Guardian tanks are completely reliant on their def CDs to survive any type of FF. Too bad the two good ones are on a 3m cd. Outside of warding call and saber ward, guardian tanks are easier to kill than sin tanks.
People want guardians a MT mostly because of g leap and their spammable free aoe slow that keeps the whole enemy team slowed at all times. If the guardian lost those, sins would probably be better MTs in pvp.
And the 0/27/14 spec does plenty good dps, and will nearly hold it's own against focus guardians on most maps, but with the extra utility of double stealth and fastest node reinforcement. Plus focus spec is inevitably going to get nerfed somehow.
It just seems to me (do not have my jug to 50 yet) that jugs are just way better at tanking than sins. Yes sins have stealth and do better damage (at least single target) than jugs when both are wearing dps gear but the better teams for ranked usually want a good tank jug. Not full tank but a hybrid, at least up to unstoppable in vigilance.