I'm not professing to be an expert in patent law by any stretch, but some of the areas that have been brought to my attention are on the pharmaceutical side. For example, one area is how long you're able to keep information proprietary that you, as a producer, generated to support your patent case, instead of having others simply walk in and use the evidence that you've shown, with respect to the efficacy of your product, to prove the efficaciousness of their product.
One of the other things that comes to mind is, again, in the pharmaceuticals, where you have such a lengthy process of testing by regulatory agencies before a product is actually allowed on the market. The patent protection period needs to encompass when the clock needs to start.