Depends on the market. For most software patents, even 3 years might be too much, as in that time the "invention" will be already obsoleted by something else.
I strongly agree with GP that companies should not be able to just sit on patents. The ability to literally prevent useful ways of thinking from manifesting in this world is something that goes against the core justification of the patent system.
Also, I'd like to see much bigger pressure put on quality of patents. All patents are eventually meant to go to public domain, and the public is meant to be able to recreate the invention from the text of the patent. Therefore, I believe a patent should not be granted if it isn't demonstrated that it contains all and accurate information necessary to reproduce the invention.
I strongly agree with GP that companies should not be able to just sit on patents. The ability to literally prevent useful ways of thinking from manifesting in this world is something that goes against the core justification of the patent system.
Also, I'd like to see much bigger pressure put on quality of patents. All patents are eventually meant to go to public domain, and the public is meant to be able to recreate the invention from the text of the patent. Therefore, I believe a patent should not be granted if it isn't demonstrated that it contains all and accurate information necessary to reproduce the invention.