I don't know what interest the general public have in historical docket filings but I do know that Pacer is very useful in following ongoing cases. Check out groklaw.net where significant IPR cases are followed and the owner/blogger often has to spend a fair amount of her own cash to make the information available to her readers. So while it seems a low return effort to maintain a partial copy of PACER it seems a good idea to be able to crowdsource PACER documents for cases that are ongoing and of public interest. Groklaw should be interested in this browser plugin for sure.