A requirement of 750 rep to edit community wiki posts seems too high. 750 rep will take weeks for most users to acquire. Even an extremely active user will take at least 4 days (at a max of 200 rep per day, neglecting bounties). A user who has invested the time to make it to 750 rep is probably on their way to earning the 2000 rep required to edit anyone's post.
As I see it, there are two options here:
- Lower the rep required to edit community wiki posts significantly (I'd suggest to 100), so that they really are Wikipedia-like (e.g. anyone can edit).
- Stop calling them "wiki", since they are nothing like Wikipedia, and come up with some new term which only implies that no rep is earned from the question ("unaccredited" or "unowned" or something).