To take this to the obvious parallel of software patents, patents get a lot of (deserved) criticism these days, but they exist for a reason, ans serve a purpose which I think is arguably still valid. Excessive patent length and patenting trivial things is bad. So is people stealing the hard work of others. There is a sane middle ground we should be shooting for, not wiping patents out entirely to the detriment of most (arguably all, in the long run).
Incidentally these types of plant patents AND software patents are the two categories that are patentable in the USA but not in most of the rest of the world, so they definitely straddle the line of patentability.
