I have a dumb question: it may already be answered in the 24 pages, but i am too lazy to read them all.
Why not just monkey with the xp tables so that progression is slower and progression above level X (6,8, or whatever) is really slow?
Because it's not just a matter of "characters progress too fast". It's a matter of "I don't like that the world (characters, NPCs, and monsters) continue to simply get bigger and bigger".
It's kinda like some of those rpg games I played back in the day on consoles. At "first level" you'd start out inflicting 150 points of damage with each attack. By the time you finish out the game, you're doing thousands and thousands of points of damage.
Of course, the monsters have thousands and thousands of hit points.
All that's happened is the numbers got inflated.
Running an E6/E8 game stops the number inflation. Hit points, skills, saves...all of it. There's a finite limit and it doesn't take more than a year of play to reach it.
One problem with slowly down XP gain, is it leads (or has the potential) to a feeling of "stagnation". You keep showing up session after session, and your character just doesn't change or do anything. People _like_ to level. They want new bits for their character. That's why E6/E8 goes with the feats after you hit the level cap. That way the character can continue to "grow" without having a massive inflation everywhere.
Your suggestion, on the other hand, would do a better job of somewhat emulating AD&D-style play (or at least, rates of leveling). Or a hybrid thingy. Anyway, around that area.
Sort of.
See, the thing I noticed? AD&D had "slow" leveling because most of the DMs saw the rules for giving XP for treasure and said, "Screw THAT!!! They got the gold, they're lucky to be alive. No way they're going to double dip and get XP for getting the gold too. The gold is its own damn reward."
Hand out XP for gold like you were _supposed_ to do, and the leveling rates aren't really _that_ different. It's just that 3rd ed rolled around and the XP became all focused on killing things, instead of killing things and taking their stuff.