I suggest that rather than limiting effects of patents, it is easier to exclude obvious ideas. By this, if two identical ideas are submitted as patents within a designated time frame, then the patent is not novel enough.
This has several advantages:
1. The number of educated people have risen considerably that we are filing more patents in a decade than the past 100 years. Even if there weren't patent protection, ideas will still continue to be created. By getting rid of the first past the post problem, we are effectively saying we will not grant an exclusive patent for something that someone else could have invented.
2. This scheme does not impact on the R&D that requires long term investment. e.g. pharmaceuticals.
3. It makes "idea patents" easy to invalidate. e.g. using a phone to play music.
unfortunately, obviousness is a very difficult thing to test for.
May be a test for obviousness is that an expert in the field is able to deduce the "inner workings" by only observing the result of applying the patent.
Thus, a pharmaceutical patent would continue to be effective under this test (you can't really tell the inner workings of a pill by looking at the pill). However, you can tell the inner workings of a bloody rounded corner, or using a phone to play music.
I say this, because patents were intented to incentivize people from hiding their secret ideas so that society at large benefits. If your idea can't be hidden, then there is no need to grant any monopoly.
Say before wireless, you had to check your email over a wired connection. Someone patents the idea of checking email over radio waves. If multiple people came up with the same idea, and lodges the same patent within 6 months of one another, then it is not worthy of a patent.
This has several advantages:
1. The number of educated people have risen considerably that we are filing more patents in a decade than the past 100 years. Even if there weren't patent protection, ideas will still continue to be created. By getting rid of the first past the post problem, we are effectively saying we will not grant an exclusive patent for something that someone else could have invented.
2. This scheme does not impact on the R&D that requires long term investment. e.g. pharmaceuticals.
3. It makes "idea patents" easy to invalidate. e.g. using a phone to play music.