Hello, Everyone!
Recently I noticed that a lot of classic Roblox outfits no longer work simply because of default clothing overriding them, namely the classic zombie from the early days of Roblox.
I’d like to see this changed as it would allow alot of classic outfits to be brought back. Plus, the characters aren’t completely nude, so I don’t see the point in forcing default clothing with these types of outfits.
How the zombie outfit looks now:
How it’s supposed to look:
This change was made ~2 years ago to try to prevent “nude” characters from appearing (would link the announcement, but I couldn’t find it). Typically, this is done by having the torso and legs being the same color, with the arms and head being unimportant (“masks”, “jackets”, etc). Having the default pants is really annoying, but I don’t see Roblox changing this, probably because of the media coverage they have received in the past.
I thought it was done by making a character completely naked?
There are ways to verify if it’s actually nude or not - and I think the only way should be to have all body parts be the same color, as it should be. 
To add to what @TheNexusAvenger said, more preventative measures against making “nude” characters was taken on the side of moderation. If you upload anything whether it’s a decal, a t-shirt, a shirt, or whatever, and it’s a blank completely transparent image, you will get a moderation warning for it, as they believe you’re attempting to upload clothing in the pursuit of making yourself nude.
People could make your zombie outfit colors, and then make a shirt where the arms are the same brown, and boom, now they’re “naked” because the green arms change to brown. But, they’d skirt underneath your proposed idea to prevent it. Honestly, you should just look towards making clothing that re-creates the desired look (like I’m assuming is what you did to get that 2nd preview image) and you could sell it on the open market & hopefully make a bit of cash from those who want that classic look. I know Noob outfits sell pretty often, as I see people still dressed into them. (yellow arms, blue torso, green legs)