That is why the whole game needs to be revamped. In my opinion we are all throwing around these wildly complex solutions trying to make up for something that is fundamentally broken.
What does it mean to be a mage in TES?
- Why be a mage over something else if warriors and thieves can use magic as well?
- With zero checks and balances for using magic...what is the point of magic?
- Should mages even have anything beyond simplistic warrior or thief skills?
- Should mages be allowed to wear any armor or quiet clothing?
This is not a team based RPG where you have specialized classes, this work well in a team but fails totally in a single character game.
You become a mage by using magic skills a lot, same for all skills.
To explain this start Oblivion or Morrowind with a high level character who are a novice in destruction magic. Enter a dungeon and use only destruction magic, how many second do you last
Yes you can make very powerful characters with combining skills, get good in destruction magic and blade, this give you the option to do ranged spell attack and cast weakness to boost damage from your magic sword, this is called spellsword.
Mages in heavy armor who uses destruction magic is part of lore, they are called batlemages.
In short a mage is someone who are skilled in magic, they can also be skilled in other things.
Quite possible smithing and enchantment are a very good skill combination in Skyrim.