In ordinary language (though perhaps not in law), "truly innovative" is not the opposite "obvious". I believe the language involved in US patent law is "the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains." So in my non-legal opinion, the standard is two low on it's face, whether or not it's enforced. I wouldn't consider a solution obvious if it took me even an hour of brainstorming, but IMO that shouldn't typically warrant a patent.
Regarding your proposed test for patentability, I've thought about similar tests before. There would be many practical difficulties, like deciding who frames the problem. Some of the most innovative inventions are just properly identifying a poorly understood problem. But I think something along these lines is the right way to go.
Another possible variant would be to force licensing of the patent for an amount proportional to the expected cost of developing the solution from scratch, maybe weighted by the potential market.
Regarding your proposed test for patentability, I've thought about similar tests before. There would be many practical difficulties, like deciding who frames the problem. Some of the most innovative inventions are just properly identifying a poorly understood problem. But I think something along these lines is the right way to go.
Another possible variant would be to force licensing of the patent for an amount proportional to the expected cost of developing the solution from scratch, maybe weighted by the potential market.