The system I propose we use is a homebrew type that I made, and it borrows heavily from 3.x/ Pathfinder
Everything will be on excel spreadsheets for reference if we get this off the ground
What I did was keep the Abilities, Saving throws, hit points as they are, and then abolished the exp class based level system, and adapted it to be skill based
As such I added skills for specific weapons and styles of magic. To start you have many more skill points than in the books
There are no classes or levels or experience points in this revised system. If you want to advance your character, you will have to actively role-play them using their skills. As they use the skills (Successfully or not) they will slowly advance. To build up hitpoints you would have to put skill points in endurance. To become more skilled with a shortsword you will have to practice with one. To gain acess in higher levels of alteration magic you will have to research from existing libraries and cast Alteration magic as you go along. There is no waiting for the next chunk of XP to advance, you will advance a little bit each session, instead of all at once from some pre-determined level of experience.
There are no character classes or feats in this game like 3x or Pathfinder. If you want a fighter type character, spend all of your initial skill points in a few hand or ranged weapons, armor and shield skills, and possibly weapon smithing or armor repair. If you want a Wizard, spend your skill points in knowledge arcana and the various schools of magic. If you want a druid, you would put your skill points into things like knowledge nature, herbalism, animal lore, nature magic etc. The possibilities are endless and not as strict, allowing for more flexibility.
The magic system is likewise heavily revamped. Spells are not memorized and assigned to slots before an adventure. I have elected to have a more traditional Magic Points (MP) system for Wizards, and a Fatigue point accumulation system for Sorcerers, (There are various styles of magic in this game)
I like this system better than the 3.x because it forces players to focus on the story, and developing their characters through usage. It also eliminates their obsession with books and wanting to stop play to reference some rule somewhere to give their character an advantage.