Another call for input, and more stuff to start thinking about....
FEATS
These are split across two files: feats for PCs, and feats limited to monsters. I think the simplest thing to do at this point is just to sort out the feats that strict E6 PCs cannot attain, and move those over to the Monster Feats (but keeping them categorized). The E6-specific feats in Stoughton's original doc will have to be added in, as well.
At some point (after monsters are sorted out, I suppose), we'll have to completely remove any unused feats. However, aside from really obvious non-E6 ones, tracking down those unreferenced feats might be a hassle and something to keep an eye on in the long term.
[edit] Also, should we include the General feats from other WotC Divine, Epic, and Psionics rules? (I believe there are fewer than 10 that I can find at d20srd.org, iirc. Actually, I just counted, and there are actually roughly 25 E6-appropriate feats from other WotC ogc.) Ordinarily, I'd say no; however, because E6 is very feat-dependent, and because these are "official" WotC OGC, I'd like to consider this.
Any other ideas, comments or suggestions on how to handle/approach feats?
MONSTERS
Ugh. This could get messy. For starters, I think we ought to simply chop at some arbitrary CR, then add/delete later. I'm leaning toward CR12 (because those are solidly "overpowering" at ordinary 6th level), but I'm open to other opinions. According to the database at Pen, Paper and Pixel, there are 586 monster statblocks in the SRD (not really a monster count, but it's the quickest number I could come up with). Chopping at CR12 drops that to 486, whereas chopping at CR10 drops it to 448. Not a lot of difference.
Ideally, this will get pared down further by selecting other criteria to narrow things down (eg, spells referenced)-- but after skimming the various "MonstersA-Z" files, plus the two "SpecialAbility" files, I'm realizing that this will be difficult; we'll likely have to return to this a few times to get it internally consistent.
So for now, I think cutting at a specific CR is good enough, if only so we can continue making progress and get to that First Draft stage. But in the meantime, be thinking about how to further prune the monster list down; and how/whether to reference monster special abilities or powers that reference non-E6 spells, class features, or other excised material.
Seriously, I'm more than happy to hear any and all suggestions on this, because it's potentially a big headache!