That said, consider for a minute the consequences. User interfaces in the MMO world are not known for their originality - if you've played one hotbar-based MMO, you will find that the competition has intentionally designed their systems to reduce your learning curve when you take their product for a test drive. All talk of "WoW clones" aside, is this really a bad thing for players? These interfaces survive not just because they are familiar, but also because they work.
In that context, I'm concerned about a massive company with massive numbers of lawyers establishing a precedent for killing games based on their similarity to a competing product. The US system of permitting patents on abstract concepts has created an environment where companies can no longer create new devices without paying someone - either a competitor or someone who never intends to market a product - for broad patents on the concepts behind their inventions. Small and independent developers face enough challenges without the potentially prohibitive costs of licensing concepts from the EA's, Activisions, and - yes - Zyngas of the world who can afford to litigate.
I realize that the iterative evolution of MMO's, the conduct that Zynga stands accused of, and the state of the rest of the US Intellectual Property system are potentially three distinct points. I'd just like them to stay that way.