Hmmm...

[Amechra]

I had an idea earlier; what if you took normal DnD, and then hacked away all HD after 6th level?

"You are talking about e6, you idiot." I hear you all cry, but that isn't what I'm saying; what I'm saying is more on the level of:
-You level as normal; however, after 6th level, you no longer gain BAB, Skill points, and Base Save progressions.
-All "fiddly bits" are capped at what you could get as a 6th level character using RAI; so you would be limited to 3rd level spells, 3rd level powers, and so on and so forth.
-You would still be getting your bonus HP from Constitution and levels; however, you lose the amount you would roll for beyond 6th level.
-You still get feats and such as normal.

So, how would this change things?

[Flay Crimsonwind]

So normal dnd without class features past 6.

Or e6 with HP gain?

Or do you mean that I could get to lv 6 as a warblade, then progress as a wizard, and by ECL 12 have 3rd level spells and 3rd level maneuvers? Then take.... binder, whatever, and have the ECL class features of a binder 6/Wiz 6/ WB 6 by ECL 18? In simplest terms, not that people would necessarily do that.

[sirpercival]

This sounds an awful lot like 1&2e, where you don't gain HD after a certain point but you gain class features (and a small number of bonus hit points).

[RobbyPants]

This sounds an awful lot like 1&2e, where you don't gain HD after a certain point but you gain class features (and a small number of bonus hit points).

At least back then, your saves and attack bonus (THAC0!  ) went up down. This version wouldn't do that.

Near as I can tell, as written, it would do what Flay suggested in his third line, which would encourage multiclassing a lot. If it's not supposed to be that way, it just looks like e6 + Con mod to HP afterward.

[Flay Crimsonwind]

Hmmm..... then in epic, you'd get those wacky spells like Hallucinatory Terrain, Improved Invis, and Polymorph.

Actually..... that sounds way more fantasy....

[Amechra]

Alright, a slight modification to the idea: everything proceeds as in normal DnD, but spells don't exist above what a 6th level caster could use, maneuvers above 3rd level don't exist, psionics is limited in a similar manner, and so and so forth.

The thing is, you still accrue spell slots, extra maneuvers known and readied, more powers, a higher ML, more vestiges bound, etc.

How would this change the game?