I would guess it is, but I wanted to hear some opinions, especially in the light of running with PUGs only and their possible stance on being with a tank that is clad in only blues.
It is, as long as you're following the basic rules of tank stat assignment, namely, Accuracy and Alacrity are terrible and you want to minimize Endurance while maximizing mitigation. A great place to start is to pick up the crafted 28 Immunity and Sturdiness enhs: they're the second best tanking enhs in the game and they can be crafted for pretty cheap (they were going for ~45k each last I checked on Pot5, and you only need 7 of them; that's 315k for enhs that are going to last you for a *long* time). Another good thing to do would be to pick up 4 pieces of the Campaign set armor with your Basic comms: with the 4 piece, you'll manage better Shield chance *and* better outright damage reduction than you would with straight up BM gear. With those, you just need to wait until you get multiple pieces of the Arkanian/Underworld set pieces to start replacing them for an actual upgrade. If you have shells that you like, as well, you'll want to work on getting your augs in place: a full set of augs will make up 20-30% of your total mitigation itemization budget (depending on gear level; at entry level HM FPs, it's closer to 30% whereas at top tier, it's ~20%), so it's a great way to crank the living hell out of your mitigation stats without setting foot in any HM FPs yet.