How about taking a cue from the music industry for derivitives?
Lots of air has been spent talking about the quality of patents, and I agree, most are horribly arcane, vague, trivial, or even completely deceptive, but we need to start at the back end.
I believe a patent should require no more than 2 full pages to describe fully, with additional articles added to specify applications for it, for example: a waterwheel "invention" might specify it's function, spinning in connection with water, but then to clarify for the layman in regards to it's assertion, add an article to show it's potential use as a power/work generating device, and another article showing it's potential being a rotary paddle when the power/work is generated by something else... this is a crucial bit I'll get to below...
Now the back end argument is simple. Today, we have DJ's and remixing "artists" who have never invented a sound, and are able to produce new works of "art", they are allowed to sample, modify, and reproduce sounds to form new tracks. I know the negotiating with the various rights holders can be tricky, publishers, authors etc, but in a patent situation, this needless division wouldn't exist (or maybe it should? manufacturers patent vs scientific patent?)
So let's say patents are as they are today, complete and total rights to an idea, except that we add a compulsory licensing system, so that anyone who wishes to use a given patent in a derivative/inventive way can (ie. not directly competing). Then the "application" article appended to each patent would be critical to enforceability, every intended use would have to be spelled out to be covered (amendments could be made to add more of course), and the rights to it would stop there.
Therefore, if someone were to invent a whole new application for a patent, they could enjoy patent protection for themselves, with a mandatory licensing fee or royalties to the original patent holder (there could be a standard FRAND scale here) ....
Imagine someone named George invented a food processor, based loosely on a patented propeller designed for aircraft and boats originally, but the patent had never listed that as an application, then George could file an amendment to the original patent with his application of it. This would ensure his "invention" or "novelty" is permanently associated with the original patent, and the coverage of his rights is clear to everyone, and he would be free to assert ownership to that application of it only, provided he maintains his licensing of the original patent....
And perhaps the best part for the existing patent owner, if George's business ever defaults on his licensing scheme, or goes out of business, the original patent holder can file an amendment to assume ownership of the application.
Now how do we make this happen? :)