So yeah, it's not just me? I suddenly feel like less of a derp.
I didn't notice it either.
Frankly, I was disappointed that they only wore their alternate costume on missions, in ME2 they wore it on the ship as well. It felt like regression as ME1 had the same problem with armour (particularly noticeable on Virmire).
I didn't mind that so much. Indeed I think it would have been better if, like Shepard, most of them had "casual" outfits that the *only* wore on the Normandy or in visits to the Citadel.
What does bother me though is that they still do that thing where certain characters will wear nothing but a piddly little plastic breath mask in hard vacuum (or nothing at all in the case of Jarvik.) I mean that can't me good for you, can it?
I mean Liara wore a full helmet and armour at the start of ME2, so why not now?
Also, anyone notice that the thing in cut-scenes with the magically appearing Avenger rifle has actually gotten worse? Not only does it appear when you and/or your squad mates are not carrying Assault rifles at all, but now it will also occasionally appear even if you are carrying one of your own. I noticed the same thing with the pistol a few times too. The basic predator (?) model would show up regardless of what I had equipped.