Professions and Armor Types

I was wondering why are some Armor Types specific to certain Professions? In GW2 Specific roles linked to a certain profession like damage dealer and Tank are not really a thing. Wearing Heavy Armor doesn't make you a tank nor does wearing light armor necessarily mean you are a damage dealer. Instead your stats are the deciding factor. Why then can't a scholar class wear heavy armor if it decides to take a tank role or simply tankier stats? Why does the scholar that decides to be tougher wear a robe instead of a plated armor? It seems counter-intuitive that the Person wearing a robe (as for example in full Soldier or Menestrel stats) is more resistant than a Person wearing a heavy fully plated armor (in Berserker stats).

Which brings me to: It would be kinda neat if you could use the skins of other armor types to fit your playing style. (Note: only the skins/appearance as it seems understandable to me that the slight differences in armor might be crucial to balancing the professions). Personally I quite like the idea of having an heavy armored battle necromancer or a revenant in leather armor. Then again i might just have poor taste :D . What do you guys think?

It would be interesting if each armor weight could be used by all professions, but each came with its own passive bonus (say, extra armor, endurance regen, or cooldown reduction). Right now squishy characters don't get much of a DPS boost to compensate.

Would you really see a spell-slinger wearing full plate armor or a warrior in soft padding?

Even if the skin is only a visual of what is worn, keeping the delineation of armor types is here to stay.