I made a minimalistic mod for the Shifter prestige class for personal use, and decided to share it here. I prefer to keep my characters compatible with any mod I might import them into, so I don't like extensive character mods like the prc very much. This little mod (if it even is worthy of the name) only edits shifter specific files and doesn't add anything new to the game which would break in another module.

What the mod does:
1. it changes the requirements for the Shifter class.
-Alertness has been replaced with Spell Focus:Transmutation
I considered Great Fortitude instead, but this ties in nicely with the second change, and alertness was a bit of a wasted feat anyway.
-A character without Wildshape can also qualify for the class by having either Arcane Defense: Transmutation or Greater Spell Focus: Transmutation.
Now wizards, sorcerors and clerics can also become shifters, as long as they somehow specialize in transmutation.
-Caster Level requirement raised from 3 to 5. Doesn't affect the druid, since they only get Wildshape at level 5 anyway, but it prevents the other classes from getting access to the class earlier.
2. Removes all epic bonus feats until shifter level 28, where normal progression continues. Don't worry, you get something in return for this sacrifice.
3a. The Shifter now gets granted the following feats at the following levels:
11: undead shape and perfect health
17: outsider shape and blinding speed
20: construct shape and DR 3/-
23: DR 6/-
26: Dragon Shape and DR 9/-
3b. The epic bonus feats available to the shifter (also as normal epic feats) have changed to:
epic reflexes
epic fortitude
epic will
epic toughness
epic energy resistance
epic prowess
armor skin
superior initiative
great constitution
epic spellfocus:transmutation
improved combat casting
automatic still/silent/quicken spell

How to install:
-download the three files
-rename cls_pres_shiftr.jpg to cls_pres_shiftr.2da
-rename cls_bfeat_shiftr.jpg to cls_bfeat_shiftr.2da
-rename cls_feat_shiftr.jpg to cls_feat_shiftr.2da
-copy them in your override folder

done!

Notes:
-If you don't want the requirements changes, don't add cls_pres_shiftr.2da
-If you don't want to lose your epic bonus feats, don't add cls_bfeat_shiftr.2da
-If you don't want the new feat list+ automatically granted feats (not recommended if you're a non-wisdom caster), don't copy cls_feat_shiftr.2da

Let me know what you think! I'll be happy to change small things on request if you're not comfortable editing these things yourself.