I know I'm not alone in my insane sewer adventures, diving in there for the fifth time to let rats beat on me for awhile so I could get an endurance bonus on my next level. That or buying/making a cheap spell and setting a weight on the 'c' key or just holding it down while you run around. That stuff gets old and boring fast, but (especially with the way the leveled system works) simply ignoring your stats can be frustrating, too. Even if you never go the extra mile and max a character out completely it's annoying to think that you have to level your minor skills more than your major skills starting from level 1 if you ever want to max the character out. That (and the leveled system) actually encourages really twisted characters where your major skills have nothing to do with the way you play.

My leveling system basically gives you credit for every single skill gain across the life of the character. If you "accidentally" gain mercantile while selling, or security while picking a random lock in a dungeon it's not going to mean a wasted multiplier. That way when you play a mage type and you have to run away from things while blasting them, eventually all that athletics adds up and you see a real increase in your speed. You can play your mage (or whatever character) exactly how you want, focusing on your specialties and major skills, and still be able to max out your character (if you want to). It's balanced so that your stats don't go up too quickly, but you also won't need to grind out all 3 skills related to one stat in order to get that stat to 100 or higher. If you do wish to grind out all three skills you will find that your stats can go slightly above 100, but not far enough to ruin the balance of the game.

The 'light' version does nothing more than has already been mentioned, levels are still based entirely off of major skills and you gain one level every 10 major skill gains. The 'normal' version has 7 combat skills, 7 "half" skills, and 7 non-combat skills. One level is 8 points in combat skills, 12 points in "half" skills, or some combination of both (it's all floating point math). If you're playing a heavy combat character you'll level about as fast as you did in the normal game, or perhaps slightly faster depending on how thick the fighting is and how little you raise any other major skill. If you're playing a character that does a lot of non-combat things or generally uses underpowered skills (hand to hand for example) you'll level slower than you would in the default game. That has the end effect of making the creatures you fight scale to your combat ability (makes sense to me) instead of your speechcraft (works for some people).

Regardless of which mod you're using, you get a normal level-up screen and you get to pick 3 stats each level. Those 3 stats each get a bonus point in addition to what they get from skill use. You can use them to level up stats related to skills you aren't using and don't want to, or you can cram them all into your primary stats and transcend godhood that much sooner.