Self-policing works where people have integrity and are willing to criticize their friends. In reality, it's too much to ask of many people, and there's no need to ask it. It would be a simple matter for the Foundation to find a couple of mature, truly independent-minded volunteers (who couldn't care a stuff about being liked by the other checkusers) to act as a checkuser oversight panel. The very existence of such a panel would instantly reduce checkuser misuse.
The foundation generally avoids getting involved in the running of the projects except where absolutely necessary. How about you wait and see how ArbCom rule (and the reasons they give - those probably will be private, but presumably you'll be privy to them as a party) before passing judgement on them?