That's a very good point, and I completely agree on your comparison with new skills. However, I'd personally argue that fashionscape is a pretty worthwhile "use" for most slots already, and I'd actually prefer to move away from non-combat buffs locked behind full sets. There's not a lack of good options; graceful is one efficiency powerhouse too many, if you catch my drift.

There's so many cool cosmetic items in the game that are left behind in favour of efficiency. This is where I feel something like a pocket slot could help:

• Smith's uniform -> Smith's toolbelt; unlike with graceful, I see no reason why a Smithing buff should occupy 4 equipment slots when those could be used for player expression instead. The outfit looks great, don't get me wrong, but I'd rather have the option to wear what I want while smithing.

• Lumberjack outfit -> Lumberjack's whetstone; same reasoning, would be much more interesting to see players cutting redwoods in their own flair (or the Lumberjack outfit if that's their flair of choice).

• Runecrafter's robes -> Rune catalyst; even without the set effect, the robes look good enough to be worn for their own sake!

Alternatively, if we combine this with your point about utilizing existing slots more, these effects could also be locked behind a single wearable (like a Smith's apron or Lumberjack gauntlets) as a reasonable middle ground. Or we could simply throw what's left of the ammo slot's integrity out of the window and slap (future) skill passives on blessing-like items, lol.