Since the Constitution does not define NBC, the courts must look to other sources in making it's definition of NBC.
If you can get your proposal passed, you will have a court issuing a ruling on the issue, although I am not sure SCOTUS will necessarily rule on it.
You should know that while the severability clause may save constitutional provisions of the bill if other parts are found to be unconstitutional in the final ruling, it does not have an effect on the original injuntive relief. Although an argument can be made for a more narrow TRO, I believe the court will enjoin the entire law until it is decided and all appeals are exhausted. I further believe there will be challenges to the law, constitutional and otherwise, that we have not discussed.
At this time I hope you have thought about lining up sponsors for the bill and expert witnesses to testify in committee for the necessity of your language. I am sure you realize that you are going to have to educate most, if not all, legislators because they think the entire issue revolves around the BC, and have not even heard of this 2 citizen-parent theory. I think I saw a post by Kenny Bunk on another thread that he had talked to several legislators and everyone said the issue was settled because Obama was born in Hawaii. I realize that is anecdotal, but I think it is an issue you need to address if you expect to get anywhere with your proposal.
All this being said, I sincerely wish you luck in getting a ruling on the 2 citizen-parent theory.
My hope is that they get to deliver it themselves in front of the SCOTUS. Your point also has as much popular support as the case against Obama's eligibility. That is a huge problem for the country, and certainly would have already led to civil strife in any number of our sister American republics! It is also weakening our country because, no matter what the outcome, this administration has the taint of illegitimacy about it.
This is why I and many others are calling for one state, 1 governor, 1 state attorney general ... to keep Obama off the ballot in 1 state. It actually has NOTHING to do with Obama .... much ..... What it has to do with is getting the SCOTUS to narrowly define Article II ... one way or the other... and quickly.
A Constitutional Republic simply cannot have a divisive question of this magnitude remain unanswered. IMHO, Team Obama cynically took advantage of the Chester Arthur case. At the time, had the people known that Arthur had lied about his origins, which has only very recently been definitively proven, he would have been dragged bodily from the White House, or worse.