I think the problem is CF convincing Gainax to even consider CF seriously... among funding to actually buy the license. The other worry is that PM4 has, I believe, professional voice acting. This might cost big $$$$ to get the rights for. Yet, that hasn't stopped CF from choosing alternatives.
As for issues with PM4, the only issue is that it features underage girls (like that was ever a problem for CF) and you can still marry your adoptive daughter (which might be a problem).
Otherwise, I don't see much in the terms of content problems. PM4 doesn't have any nudity in it unlike PM2, but the freedom of PM2 is not in PM4. For example, you can't work your daughter to death, it's just not possible. The game, however, features a variety of in game events that need to be triggered to get different endings. Not to mention your daughter is an oh so adorable blondie.
I doubt any contributions will help in obtaining this endeavor but... *passes hat around*