Just a tip I discovered, but with some caveats:

Aside from moving MAT poses to the Camera folder, and renaming all the .PZ2 files in them to .CM2, I just ran into another wall with too many folders in the Camera folder, as well (I'm using PPP), so I had to go back to the Pose folder and try some control efforts.

The INJ and REM poses for M3, V3 and S3 take up an enormous number of the available spots in the Pose folder, so I added "INJ" or "REM" to the file names in all of these folders, then consolidated them into single "INJ-REM" folders for each subset, eliminating something like 33 folders.

However, I found one very odd thing in the V3 "All Head Morphs" and "All Body Morphs" PZ2s: rather than referring to the deltas, as the M3 and S3 files do, these V3 poses refer to the other V3 poses, so I had to edit these poses, as well, changing both the paths and the filenames of the PZ2 files in order to correctly access them. It works! That just surprised me; anyone have an idea why the V3 "All" sets don't refer to the deltas?

There are also some character sets that do this, apparently; don't know why, because it's just plain stupid and requires your pose files to be nailed in place. >:( The alternative to hand editing is Correct Reference Pro from Hogwarden. I don't have it personally, but it's received lots of recommendations on these forums.

I don't know why, but it was a real pain. I use P5 and I make extensive use of the hierachical folder system, and I found this one out the hard way. So I fired up Textpad and fixed the "All" sets. And after testing I zipped the results back into a copy of the headmorph and bodymorph packs - if I ever have to reinstall the whole kaboodle I won't have to do it by hand!