I've Played E6, How about this...

[Hallack]

I have played E6 games and in truth like them fairly well.  They do a pretty good job of limiting the top end magics and stuff to keep a game grittier in function while still allowing some pretty cool magics if it is wanted. 

In the future instead of doing E6 style with the sudden shift in rules, feat, additions, etc... to make compensate I am considering trying something a bit different that I expect others likely have tried.

I would like to get your thoughts and/or impressions.

My idea is simple.  Just pick a spell level depending on the level of magics you want in the world and you can't learn anything higher.  You still otherwise level and accumulate higher level slots normally but those slots can only be used for the knowable spells and metamagiced versions of the same. 

There is a slew of consequences but in general I think you should be able to play 1-20 advancing class features normally.  Yeah, there will be some that would be outside the Spell Level limit and thus likely need house ruled too. 

You should be able to continue using a broader range of challenges.  Magics would still be awesome but melee types probably hold value to the party better over the long haul.

More consequences of course that that hits some of the highlights.

Whatcha think?

[Nunkuruji]

It depends if you limit the higher level Sp/Su available of the higher CR DM Monsters under the same rule.

In E6, you're never really expected to deal with probably anything higher than CR12.

Otherwise you end up losing the war against things you're supposed to intelligently be able to counter or recover from.

For instance,
no Dimensional Anchor to deal with Teleporters/Plane Shift, common among higher CR outsiders
no Disintegrate to deal with Forcecage or Wall of Force
no Greater Dispel Magic to deal with ever increasing CLs

It can work, and it'll feel gritty, but the DM has to be careful not to present something that is uncounterable.

[PlzBreakMyCampaign]

The above should mean: watch out for abilities that mimic spells of a higher level than what is banned. What it actually says isn't a problem due to the usual existence of on-level counters.

[awaken_D_M_golem]

1e (and 2e iirc) had a Magic Rating to any universe.  So a -1 level MR wouldn't have 9s or Epics, except for massive shenanigans.  And a +1 level MR would have level 1 spells as cantrips, level 2 = level 1s, etc on up, things get kinda hazy at the top end.  The scale here would go all the way to +/- 10 ; meaning no magic at all in a -10, and even the gods would have big big trouble ; and in a +5 MR even Divine Minds would be scary.  As a for instance:  4e feels to me like a -5 MR universe with level 4 spell equivalents as a max.

[Hallack]

1e (and 2e iirc) had a Magic Rating to any universe.  So a -1 level MR wouldn't have 9s or Epics, except for massive shenanigans.  And a +1 level MR would have level 1 spells as cantrips, level 2 = level 1s, etc on up, things get kinda hazy at the top end.  The scale here would go all the way to +/- 10 ; meaning no magic at all in a -10, and even the gods would have big big trouble ; and in a +5 MR even Divine Minds would be scary.  As a for instance:  4e feels to me like a -5 MR universe with level 4 spell equivalents as a max.

Lol, I remember them days.