Certainly, if game designers themselves cannot agree on what the core elements making up a game are, it’s troublesome that a patent official is going to decide whether a given innovation is significant enough to be protectible. Yehuda has another post where he lists off some recent patents.
It certainly wouldn’t be too hard to arrive at a large number of generic game mechanics and “put them in the public domain” in some fashion by releasing them under some sort of open source license. The question is whether you’d then have trouble profiting off of them — after all, board games are difficult to profit off of as it is!
Certainly, anything that stifles innovation as regards creative product of any sort is something to be worried about. As recent discussions here in comment threads about appropriation and reinvention of cultural product demonstrate, cloning, copying, and varying existing creative content is a critical part of the development of fresh innovative content.