(I apologize in advance if this topic has been mentioned elsewhere. I tried to run constructive searches and look for appropriate places to mention this without making a brand new topic, but 20 pages of suggestions is hard to scan through, much less 70+pages!)

I recognize this must sound silly, but could Pearl Abyss create a way to make a way to convert existing weapons and/or armor into skins for the player? For my part, I would happily go to great lengths to obtain such a conversion kit if it meant I could keep an earlier look for a character I've advanced further along.

I've not played BDO long (not even a full year until Mar 2022), but a large part of my reason for playing and enjoying black desert has been its awe-striking visuals. It is a well-balanced feel of magical and medieval and achieves its balance without getting disgusting, excessively gritty, or dark, like so many other fantasy games I've encountered. I'll also admit I'm a bit of a dress-up player too. I like the beautiful costumes and outfits the creators have offered for the players, and spend a significant portion of my characters' earnings on aesthetics, and I like most of the obtained "[Honors] costumes" one can use in the game. However, in some cases, I find myself drawn most to the looks of the earliest armor and weapon appearances. The ornate embellishments on maehwa/Musa blade skins and the giant barbs on the Dark knight's late-game Kriegsmesser models don't appeal to me by comparison to the simple tools of characters as I had them on Day 1.

Perhaps its because I'm a sucker for the look of 'magic runes' that such starter weapons have that draws me to them (I loved them on the late-game Guardian weaponry), but after much research, I'm disappointed to find I cannot take on the look of my Maehwa as she appeared when I first created her, nor does it look like I could retain the runic look of the Dark knight's first Kriegsmesser by any means currently in the game. A tool that could turn a weapon into a costume of the same appearance for another weapon would be greatly appreciated.

Seen any of these outfits? I'm sure they exist, but can anyone actually wear them without taking a hit below the Tuvala entry level? Don't get me wrong, I love that there's a season armor that is more competitive and alleviates some of the power gap, but that now means there's literally an armor class that is too low to ever be used, and as a result, a whole look that will never be seen in-game! For those of you not aware, all of these are appearances you cannot obtain as outfits or costumes. You can preview them in the character creator, but will probably never actually see them in-game. I've never even seen the two Maegu outfits since the class was created. (-and I'm totally glossing over the weapon aesthetics that you cannot find, like the Guardian shield with old English runes, and a trifecta on one of her axe designs.) Having only played some of the classes, I can't honestly testify that ALL classes have this problem, but I suspect these aren't the only ones either. Why would someone craft these only to have them never get any exposure?

These already exist for the most part.
[Balenos] Shiel's outfit box
[Serendia] Cleia's Outfit Box
[Mediah] Lucy's Outfit box
etc etc

I don't mean to contradict you, but check any of those, and you'll find none of the listed outfit boxes have these. They are for different looks than the ones I have shown.

You're talking about base clothing, the appearence's our characters have before equiping any gear.
You always have these looks avaliable if you chose them for your character's appearance, however once you equip gear, you gain that gear's appearance and no longer have your basic outfit. 

That is true for the Maehwa in my lineup, although to clarify, some of these looks come from wearing green or blue grade gear. Take Liverto gear (not sure if that's what has some of these skins, as I've had to ask around and have yet to track down what equipment actually uses some of these appearances, but bear with me here), then you have to wear gear that isn't even as powerful as Tuvala, Boss, or Blackstar gear to obtain that look. There's no other way to obtain that appearance at present.
That rather puts a damper on adventuring, not being able to use your best stuff, or not getting to look the way you want to, which I believe is why we never see these outfits on players in the game.

The first costume may be the Mystic starter armor (unobtainable as a costume), the two Gumae outfits I'm not sure about, the 4th is Grunil for Witch, and the Maehwa costume on the far right is the starter armor that you cannot use as an outfit.

OP makes a point, the devs spent time on these outfits, yet we cannot use them past our intro quest or severly hampering our DP as boss alts/late game. Would be nice if they added more of the Honor outfits. One outfit I can think of is Zereth for Hashashin, I think it's one of the most chill outfits for Hash.

Saw your comment on some of these, and while I can't testify where some of these come from, I do know none of the images are honors outfits. I whipped out my witch and threw on the Grunil outfit to contrast it to the green one above. I think you'll find it's not the same. That said, I understand why you might mistake one for the other. I think we also agree that some of the looks best for characters aren't available as outfits, which is sad.