I’m not saying “I want to transmograph my helm into an Oculus” (but considering how hard is to get the achievement, it should be possible as well 
), but please, at least, let us to transmograph any 1H weapon into any 1H ethereal weapon and the same for 2H weapons.
It would be really appreciated.
Thank you
The reason they won’t do this is because of all the combat animations that would be required that don’t currently exist. For example, if you transmog’d a wand into a one-handed crossbow, there’s no animation for the Wizard to use crossbows. Likewise, what if you transmog’d a one-handed crossbow into a fist weapon, there are no animations for a DH to use fist weapons. This is why transmogs are limited to gaining the appearance of a weapon that’s of the same / similar type. It’s not about the appearances, it’s about the combat animations that would need to be created.
You are right just partialy 
In basics you are right ofc, but its not about class at first, but about weapon type. Because in your example DH could transmog 1h/2h Crossbow into dagger, because he can use daggers, so there is animation for DH using melee weapon.
In short - you cannot transmog into different weapon type. 1h ranged weapon can be transmoged only in 1h ranged weapon. As well as 1h melee cannot be transmoged into ranged, but again only into 1h melee.
And after this basic rule there is rule of class - if you cannot equip exact item, you cannot use its transmog, even if it is same weapon type. For example - you can transmog 1h sword into many 1h weapons, but you cannot transmog it into ceremonial knives. Even if you are WD. Ceremonial knives can be transmoged only into small types of 1h melee weapons, like daggers (and knives ofc). So Meteorblade is not exact in this one, but partialy and in basics he is not wrong.
Crystal clear!
Thank you
I would like to make my wizard’s boots look like a pair of yangs recurves…