That would not make the skill more usefull, but just mandatory to take.
I hope they will refine the enchanting screen soon, I don't understand why they didn't made more clear wich enchants are exclusives. That just force you to save before any attemp to enchant and reload if you don't like the result, annoying I find.
With the current limited supply of unique weapons for some categories, I would like to see generic enchantment back (liked it in poe1) so if you don't find an unique weapon you like you can craft something better than just a standard weapon.
In the futur, be able to enchant any items (accessories etc...) could be great too.
You have a point, but i honestly think mechanics and athletics are already mandatory or close to it. What i proposed, indeed, would be bad for the vast minority of the playerbase that plays using only the watcher, without help of companions, sidekicks or hirelings.
For those who play using a party, this change i proposed would not demand any sacrifice, since you could use one companion to be the enchanter guy, just like there's the mechanics guy, the explosives guy...
Anyway, what i gave here was just a suggestion on how enchanting and arcane could work together, because i really think: 1 - arcana skill is underpowered, 2 - it doesn't make sense lore wise being an enchanter without any arcane skill, just like it would be ridiculous if the alchemy didnt influence the use of potions and poisons. But yeah, since its a minor thing and this could break the game for those who play alone, i am sure this is never going to happen.
Still, I would be happy with any change aimed at creating sinergy between enchanting and arcana skill, it does not need to be what i suggested the way i suggested,