Well, yes and no. Presuming the artwork is meant to reflect the rules of the game world, which the characters live by, a character who isn't allowed to wear armor (e.g. a D&D wizard) wouldn't be decked out in plate mail or anything of that nature. Quite often they'll instead be using a combination of spells and magic items for personal defense, which can be hard to present visually ("that cape she's wearing is actually a cloak of resistance +5, and her pendant is an amulet of natural armor +3").
Yeah, I've always been of the "crunch informs fluff" and "crunch reflects fluff" schools. If you want your PC to be viable in a harsh, usually combative, environment while seemingly ill equipped for said environment, I prefer some justification for it.
For examples: the 5E classes who can get by with minimum gear most, in my eyes, are Barbarians (Unarmored Defence and Rage making them damage sponges with only sword and/or board, plus the classic Celtic Berserker is always a fun image), Monks (Unarmored Defence and Movement allow them to dodge most attacks and dish out damage with nothing but their bare hands, plus I'm a fan of Korra and Beau), Druids (because Wildshape, plus the traditional metal taboo) and, honestly, most back-line spellcasters (plenty of protective spells), but especially Sorcerers (advantage on CON saves and the lack of a spell book). Hell, if your DM is generous with magic items or just willing to play into your concept, you can just stack on a bunch of AC boosting items (Cloak/Ring of Protection, Bracers of Defense, Brooch of Shielding, Barrier Tattoos) and wear whatever you want or nothing at all besides.
Yes, I put some thought into this beforehand. The idea of "skyclad" (a common pagan term for ritualistic nudity) adventurers gives me my kicks. I even homebrewed magic items to facilitate that "extreme minimalist" idea (a port of the Ring of Nourishment and the Ring of Comfort AKA Resist Flame/Frost since those also give you higher tolerances for extreme heat/cold). I'm weird and these theory builds are unlikely to see actual play.
In short: I'm more than fine with nudity in D&D, especially in the appropriate contexts (even if said context is 'because I want to go streaking through the dungeon"), but I don't think WotC should actively add such content to the game, they ARE marketing more to kids and families these days. And its not like the homebrew scene can't fill on the gaps.