Shadow/Assasin: The most versatile tank class in the game.
You're stating those capabilities without really getting into what the other tanks get, not to mention that you're ignoring the fact that the OP asked about role and PvP/PvE versatility. Essentially, rather than just trying to quantify versatility of performance in a single role (and, honestly, as a tank, Guardians actually get more since they've got a lot more general combat utility; the only things that Shadows get that's actually an advantage is stealth and that's only really an advantage in PvP and while leveling) you should be looking at whether the class, as a whole, can perform in all 4 of the given pairings:
PvP + tank: All 3 can perform reasonably well, though Guardians are, de facto, the best main tanks whereas Shadows are only really node Guardians
PvE + tank: Shadows are at a substantial disadvantage because of massive spikiness problems; VGs and Guardians can both perform well, but, once again, Guardians are, de facto, the best tanks outright thanks to being borked as hell at the moment (tied with VGs for mean mitigation, best damage profile, best CD suite, best utility, all tanks have the same functional AoE and ST damage/threat, and easiest to play to boot)
PvP + DPS: VGs are pretty much worthless; Shadows are pretty good as Infiltration thanks to burst DPS; Guardians are amazing as either Vigi or Focus, with Focus being almost mindbogglingly simple for how well it performs
PvE + DPS: Once again, VGs are in a very sad state because they're lagging behind average DPS a fair deal; Shadows are in a worse state since they're lagging behind a *lot*; Guardians are in a very good place because, even if they're not explicitly top tier DPS, they've still got very good DPS that only lags behind the top tier by small amount.
If you go off of *that*, Guardians are, explicitly, the most versatile, based upon role and combat type. Guardians will excel at *whatever* you choose to do. VGs will only be effective as tanks. Shadows will only be effective as a specific subset of PvP tank (which is a *really* boring type) and PvP DPS with a single spec.
So, to answer the OP's question, it's Guardians, not Shadows or even Shadow tanks.
P.S. if you're going to put out a massive list of capabilities, stick to the things that *only* that class can do and how useful those capabilities actually *are* (hinthint: Phase Walk isn't *useful*, it's a gimmick) then either make note of what the class *can't* do or create similar lists for the other classes.