Even the usual excuse YP uses for this doesn't make sense. He has previously said 'well it'd be a bit weird for a Black Mage to run around with Paladin gear on' (or something to that effect, the Jobs I might be misremembering). Point is, 'Job A from Role B, wearing X Job gear from Y role, would look strange'. If we take this at face value/direct interpretation, the only situation I agree that the logic tracks, is Job Artifact gear. There's plenty of reskin situations in the game, where the Role each gear piece is assigned is jumbled around. Here's an example:
Pic A is Aiming, from the original release of the gear in HW. Pic B is Striking, from the re-release in SB. Same model, different colours, different role
It gets even more ridiculous, when you have models for EVERY Role (all seven of them) that are almost identical, with differences mainly being palette swaps (something that you'd expect the dye system to handle). For example:
This is the gear from Great Gubal Library (normal). Ignore the top left one, that's from a different piece of content. Literally every role, all seven, have the same base model for the coat.
The infamous Shisui sets. This one, at least, got a dyeable variant added via a seasonal event (and is now Mogstation-only, which is an issue of its own)
But surely, they stopped doing that recently, it was only earlier expansions they did that and now every role has a unique set design, right?
Level 93 sets from Dawntrail. Is there something more inherently durable and 'tanky' about the colour of the Tank set, compared to the others?
I suppose maybe the logic of 'its blue, so it's the Tank one' could track, if it weren't for the Green one being the DRG/RPR set, rather than the Healer variant
So, clearly, the logic of 'it'd make jobs hard to distinguish' doesn't track at all when it comes to gear. Even when we factor out player-decisions from the argument, like 'tanking in a bikini' or 'healing while dressed as a circus mascot' as that makes YP's argument even weaker.
But, let's assume that it's a misunderstanding/mistranslation (as I've heard some theorize), and instead consider that 'maybe he thinks we want to equip Job A (from Role B) weapons, as Job X (in Role Y)'. For example, glamouring our BLM weapon to look like a WAR axe. First of all, no idea how that mistranslation would occur in the first place. Secondly, we already have multi-job Glamour items with identical models, for example:
I guess the PLD version of the Gaia Hammer is slightly different, given that it is shrunk down. Same model though
And we even have Jobs that share certain weapon aesthetics as it is! There's plenty of WHM canes you could throw on a BLM, or vice versa, and nobody would notice the difference. But beyond that, SMN and SCH literally share a weapon type, books. Yes, some are a 'Grimoire' and some are a 'Codex', and I'm aware that they both come from a base class that uses said books. But if the point of Glamour restrictions being so tight is 'so you can tell what Job someone is, at a glance', I find it hard to believe that it's so simple to tell what job players are at a glance when we can wear bikinis, casualwear, and role agnostic PVP reward sets. And even if it is a challenge to identify a player's job 'at a glance' (eg in PVP, where it's imporntant to identify threats ASAP), isn't that what the 'display Job Icon in nameplate' setting is there to help with?
Here's the restrictions that would make sense:
1: 'Appearance Source Item' must be of equal or lower ILVL, than 'Destination Item'. This is already a restriction in place, so nothing changes here. I'm not sure why you'd want to, for example, glamour a Level 10 bow when you start levelling ARC to look like a FRU weapon, but hey
2: 'Appearance Source Item' must be naturally equippable by the player. In practice, this means that to use a Level 90 Caster Chestpiece as a glamour on your Healer, you must not only have a Healer with gear of equal or greater ILVL than the Chestpiece you want it to look like, you must also have a Level 90 Caster.
3: 'Appearance Source Item' must not be designated as 'Artifact gear'. This preserves the Job Identity argument, by making sure that only RDMs can have the cool RDM hat, or that only SMNs get to have the funny SMN horn, etc.
4: If attempting to apply a Glamour from a different Job/Role, the 'Appearance Source Item' must not be a Mainhand or Offhand slot item. This prevents YP from misunderstanding what people are asking for again. Glamouring weapons within your own job would function as normal (IE turning one WAR axe into another WAR axe)
This would incentivize people even more to level multiple roles, so that they can 'unlock' access to more options for Glamour