Now with the new wardrobe system...
Because they can’t. The different armor classes are incompatible and can not be set up to be mixed and matched.
Source (page 18).
“there are some fundamental incompatible things between weight classes. (part of how we set up every armor to allow many dye channels and styles per piece). There really is no way at this point over six years since we started development to make absolutely everything work together.”
We used to be able to in the preview window before they removed it. There were a lot of pieces that mixed fine. If they really wanted to they could pick out those ones and make them multi-tier skins, especially with many of the heavy chest pieces that have no way of clipping.
Its the colors that would be messed up. Armor classes are different materials (somehow), which means its impossible to match. Black on heavy armor could be brown on light and grey on medium. I dont think Anet want to take the mass of complaints for that, lol. You can already see the poor results on some pieces within the same weight class not matching the rest.
I wish… I wish… if it only came true
Other posts: Source
Ezekiel.1985:
“With that said, you say “not possible”, and that’s just not true. It IS possible, they just don’t want to bother with it, which is incredibly stupid. Skin replacement is one of the easiest things out there in coding, when the skins are already present. It’s essentially like turning a light switch.”
Curtis Johnson
ArenaNet Poster
“That’s not entirely true.
Each of the armor weights in the game is constructed differently, which is probably one of the reasons we haven’t seen mixing and matching between different weights. It’s also likely the reason we see so many trenchcoats on medium armor—it’s specifically designed to support coats that go over pants. Light armor divides at the waist, and town clothes followed the same rules. If you read this blog post, you can pick up some hints as to how things were coded and why going back to change things would be more difficult than just find-and-replace:”
Curtis Johnson
ArenaNet Poster
Snip
" they have to go back and change all of the armor in the game to follow the same seam rules (which might break several current armor sets, too). That would be a massive undertaking," (snip)