That value can be created in a lot of different ways though - the outright rarity of an item (yes, they do exist), the memories attached to you obtaining it (maybe it took you a very long, painful farm to get this dungeon-piece or maybe a friend made you that dress) or simply that it looks damn sweet on your character.
For you "guarding your items" adds value aswell - for me it doesnt. And I even like(d) the PvP in the game - I still value my peace in the open world more than the idea to guard my items to add some weird sort of artificial value to them. I'm already attached to them and value them because of the memories they hold - or because my character looks good in them. I have a hard time tossing/converting gear that a friend made for me aswell, because it reminds me of that exact moment. I kept a pair of Heavy Darksteel Flanchard in my inventory throughout all of HW because it was the first difficult craft a friend of mine tried - I didnt need to guard them for them to have value.
On the general design... I'm not sure what you're talking about when you suggest that the gear as been looking more and more silly? We always had the odd silly piece in between, while most of the gear looks like serious robes and actual chain-mail. I dont even agree with your notion that it looks more "exaggerated" - some pieces do, yes. But when I think about the latest crafting/gathering-sets or some of the battlegear my characters are currently wearing or even current glamour-pieces like the Ao-Dai, nothing feels terribly exaggerated. The only pieces that I feel dont really fit the general aesthics of the game are those that are brought over from the chinese-cashshop (angel/demon, prince/princess) and that happend partly at our request.
In general I dont feel like the gear-design is degenrating - sure, one might not like the odd piece, but thats fair. For me they still fit into the general aesthetics of the game - and quite frankly: I rarely see someone sporting a silly outfit. And if someone does: all the power to them! Its a game, its meant to be to be fun - not be taken super serious.
(And honestly: ARR had those hideous subligars... we even had a quest that would give us golden, starsprinkled underpants - silly gear was always part of the game.)
Same goes for the mounts - yes, some of them might be a little silly, but even those are mostly rooted in this world (except the abdormitnation that is Yo-kai). If your personally dont like them, you can just pick one of the more serious looking mounts. As others have mentioned already though: Since we're all playing "your" character for the sake of the story, you'll have to share Midgardsormr.
The only notion I agree with here is that we need more mounts that are difficult to obtain - and by that I dont mean Ex-primal drops but rather something along the lines of Astrope or the Hunt-tiger: Mounts as rewards for high-tier achievements. Or make them an actual gil-sink and have NPCs sell them for 30 million.
I'm all for more options in the game as long as they fit the general aesthetics - which I feel is still the case. I'm personally not a fan of the latest gear we've got, but I'm happy for everyone who is - I can look elsewhere and I rest assured that sooner or later I'll get gear that fits my taste more again. Until then I can value that other people have a different taste and actually manage to pull off items that I tossed for myself.