So basically this is sort of a weird one but given that blizzard has done alot to enhance customization over the years I dont really see why they can simply unlock the ability for classes to equip more weapons if not every weapon of their relevent type like sword for priest or mace for warlock.
I think allowing players to have this even if it is a mild inconvinence to script classes being enabled to equip certain weapons woludnt even be that hard or time consuming since it only requires a tickbox really and the models that dont use the same spells already have the same weapons, and in general class/weapon animations are generally locked to the same animation anyway.
In other words its a mainly flavour thing but I dont see an issue with simply letting people go with whatever weapon they want.
I can see a mild argument being that raiders would aggressively need items then but they already do that so its a non-point really.
I suspect they did a whoopsi doodle and somehow hardcoded certain rogue abilities to demand the dagger tag to function which is why despite every other melee weapon can be mogged to another, swords to fist weapons and two-handed swords to spears regardless of difference in animation, size and whatever else sets them apart.
except I can easily mask what kind of rogue I am with toys and certain daggers that use sword like models.
PvP if that is their excuse remains weak and unconvincing.