I wouldn't call it broken. It's by design. Proof is that most of the "exploits" were carried over Oblivion and then Skyrim. For example, creating very very overpowered potions is possible in all games. It's your choice if you want to spoil the fun or not.
I wouldn't call it "spoiling the fun", half the fun of Elder Scrolls games is that you can become transcendent.
In Arena, you start humbly, but rise high enough that you destroy Jagar Tharn, one of the most powerful mages in the whole of the history of the Elder Scrolls games.
In Daggerfall, you're the right-hand man of the Emperor, and seek out a world-ending superweapon, and may just take it for yourself.
In Morrowind, you are a god, or very close to. The reincarnation of the Nevarine. That you can become overpowered makes sense. Bandits should fear you. Ordinary people should.
In Oblivion, you're the right-hand man of someone who ascends. You walk into literal Hell and fight demons. The bare mysteries of the world are laid clear by you. You steal the book of spells of immortal characters.
In Skyrim, you're descendant from a man who became a god. You have a gift that can shatter the heavens, and break open portals between worlds. You kill the son of Akatosh.
You're right, it is design, because it makes sense.
If anyone else here on HN is a fan of talking about what "makes sense" in the context of elder scrolls, I'm a big fan of /r/TESlore on reddit. Everything from explanations like the above, to how specific enemy groups became the way they were (e.g. the falmer in Skyrim), to theories of the economics underlying the games.
I think you might be confused with something like 'mysteries laid bare'. Bare doesn't mean foundational and if mysteries were already bare, what kind of mysteries would they be?
Unfortunately, one of the things from Morrowind which did not make it to Oblivion was the ability to make damage spells which target self. And in Skyrim they had removed the ability to make your own spells entirely.
In Morrowind I used this to create an extremely long-lasting fire spell dealing 0 damage to self. The result was a spell which cost barely any mana and resulted in you walking around engulfed in harmless flames. A really cool visual touch.
Are you sure? I have memories of making a spell that targetted myself and gave me 1pt of fire damage that I could spam to train my evocation skill (or whatever it was called).
This was 12 years ago, so it's possible that I don't remember the details correctly. I thought that "self" could not be selected for fire damage, but looking up videos of spellmaking in Oblivion this seems to be possible.
I do distinctly remember being unable to recreate that one fire spell, though. Perhaps it was not possible to set damage to 0 in Oblivion? That was part of why the spell became so cheap and allowed for extreme duration.
