Look, I'm no fan of software patents but the idea that the sale of (currently) valid patents is a threat to OSI? Look people, either the OSS you support is free and clear of infringing on patents, or it is not. Your failure to perform due diligence is your own problem if ANYONE comes along and challenges something you put out there in the world that turns out to be patented. If you want something to be open, and ensure it;s non-infringing, PATENT IT YOURSELF, then offer it freely to a patent pool under condition the software is offered under GPL or some such, THAT is how you protect OSS.
These existing patents are simply changing hands. Unless you can prove this is a specific attempt by Microsoft to do something illegal, get off your soap box. The patents in question are known. If you think your stuff might infringe, you might want to start finding out how, and change your code as necessary. The sale isn't a threat to OSS, the existence of OSS that is infringing on valid patents is a threat to OSS. Anyone anytime with an infringed patent could bring a halt to your whole game.
Besides, if the infringement was out there, why didn't Novel sue you themselves? Also, the patents novel has that they chose to open source, great, Microsoft now owns those patents, but that has no legal impact on the fact novel may have already chosen to place the code under OSS licensing, which Microsoft can never repeal (once it;s out, it;s out, and self sustaining). All it changes is who owns an essentially worthless piece of paper.