Well, only Congress can impeach federal judges. So POTUS can't do anything in that regard, but POTUS administers the Patent Office. Obama could write one little letter telling them to mark all new patents and all old patents up for review as invalid. I believe this can be done without the approval of congress. I imagine there would be a lawsuit immediately from various parties. My best guess is that SCOTUS would be forced to uphold this executive order.
In fact, Obama has done this, but not to such an extreme degree.
Obama issued five executive orders on patent reform last summer. Among other things, they require the Patent and Trademark Office to stop issuing overly broad patents, and to force patent applicants to provide more details on what invention they are claiming. One of the orders opens up patent applications for public scrutiny — crowdsourcing — while they are in the approval stage, to help examiners locate prior art and assist with analyzing patent claims.
patents.stackexchange.com is the answer to this. As you mentioned crowdsourcing as a means to scrutinize the patents, this website is exactly doing that. I hope someone on the jury panel at least refers to this website before awarding the patent trolls their victories.
In fact, Obama has done this, but not to such an extreme degree.
http://www.wired.com/2014/03/obama-legacy-patent-trolls/
Excerpt:
Obama issued five executive orders on patent reform last summer. Among other things, they require the Patent and Trademark Office to stop issuing overly broad patents, and to force patent applicants to provide more details on what invention they are claiming. One of the orders opens up patent applications for public scrutiny — crowdsourcing — while they are in the approval stage, to help examiners locate prior art and assist with analyzing patent claims.