I'm thinking about a system whereby skill progress works as in vanilla, but to gain a level (and attribute increases) you need to:
1. Have a certain level of Renown, and
2. Spend money.
I believe someone has written a mod that does part 2 (can anyone remind me of the name?), and some levelling mods increase Luck based in part on Renown (AF, Simbacca, others... ?), but I might make a mod that combines these two factors.
The idea is this:
1. I like the vanilla "sleep and choose attributes" level-up system, but
2. I dislike the "min-max for +5 bonuses" system.
One way to get rid of the min-maxing while retaining the attribute-choosing is to decouple skill use from attribute gains and levelling altogether (which some other mods have done, in various clever ways).
My idea is to make "level" into a sort of measure of "fame and fortune". The player only levels up when he's completed some quests or adventures (i.e. gotten some renown) and spent money (in one of the ways outlined below) to cement his reputation as an infamous rogue / noble hero. This has the usual effects of gaining a level: higher attributes (pick 3 to increase +4 or something similar), bigger challenges, better loot. This also allows non-combat characters to stay at a low level until they're ready to face bigger challenges, or for eager beavers to jump ahead for more guts and glory.
Here are some ways a player can choose to cement his reputation and trigger a level-up:
* Drinking and carousing at taverns while telling his tales of derring-do (or derring-don't)
* Funding the good works of the Nine Divines at temples
* Contributing to the coffers of the Mages Guild, Fighters Guild, Dark Brotherhood, or Thieves Guild
* Pledging support to various Counts and Countesses
Each of these might cost something like 200 gold * (current level). So going from level 1 to 2 might cost 200 gold worth of carousing or contributions, while going from level 15 to 16 would cost 3000 gold. Of course, the player would also need to have a Renown at least equal to the new level * 2, say.
Another way I might implement this is to actually remove the Fame and Infamy points as they come in and only restore them once they're "paid for". Thus, fame and infamy would be directly tied to level at all times.
I might also require a given level-up to have different effects on attributes, fame, and infamy depending on how the money was spent: carousing can increase either fame or infamy, contributions to the Nine can only increase fame, thieves guild increases infamy and gives smaller attribute bonuses for anything but agility+speed+personality, etc.