i got my account banned and then i kept sending harassing messages via appeals. the last one was "i hope you have to suck dick for food when reddit goes public and the stock price drops" and next thing i know my permanent ban was removed.
You don't want to delete your account until you are absolutely certain that your content will remain permanently deleted, as it appears that they are restoring deleted content.
One could just mass edit all their comments to contain some garbage with power delete suite. Of course they would have to hurry, as that relies on the reddit api for making the edits.
PowerDeleteSuite only gets the comments shown in your profile, which is limited to 1000 comments in each list: New, Top, Hot & Controversial. You need to do a data request which contains CSV files with links to all your comments, then you can feed that into something like shreddit, in order to get everything.