Earlier quoted context omitted.
In something like TF2, I'd probably rely more on the player's name than what they were wearing. If I recognize the name (even if only in the context of the one match), and know roughly how good they are, I can have my mental preference of who I prioritize. I usually play Deep Rock Galactic, which has some non-cosmetic ways to judge people's experience. Promotion(like prestige) of a class is indicated by a border colo…
The TF2 player base is too big to recognize by name outside of smaller community servers (it's still about 100k peak and this is a fraction of what it was 10 years ago at its historical peak). Sometimes you may see one or two repeat players but mostly it's ships passing in the night and that's OK! There is something to be said for games that everyone is competitive for an hour and then everyone goes home. There is a…
The holster is rare, and maybe you recognize that it's rare, but they could have just gotten it out of a drop and kept it. The Heavy with the funny flip-flops and sunglasses is probable more recognizable at-a-glance, but could have bought a bunch of cheap cosmetics for a few dollars on the market.
And in the case of keeping an uber ready, won't you have to stay pocketed long enough to learn if someone is a good or less-good choice? Even if it's raining hell on your position, you'd have a rough view of the Heavy and a kill feed that highlights the assists you're getting from them. What more is there to look for?
As for the Battlefield games you mention, my biggest issue in 5 was that all of the player models seemed to blend into the background. Most of the time, I wasn't able to spend brainpower trying to figure out who is which type of class, simply because I was too busy trying to figure out if some dull, misshapen blob was part of the map or trying to kill me. Combined with the general feel of the game (poor, imo), I was never motivated to spend enough time on it to get into anything serious. Haven't bought another Battlefield game since, and BF5 was on a steep sale at the time.