I'm playing TES I: Arena which I last played about 15 years ago.
It's an amazingly fun dungeon crawler, and interestingly it uses an experience based system and has a level cap of 20. Not to mention like in D&D there are weapon and armour limits for the various classes, e.g. a mage cannot wear any armour at all and only use daggers and staves. This is a stark contrast with the retarted learn-by-doing system introduced in Daggerfall, which essentially made your character invincible after 6 levels (if you knew what you were doing).
I really am wondering who in Bethesda came up with the learn-by-doing system... I'm thinking it was Todd Howard, considering he came in to work on Daggerfall.