I want an amendment that allows the president to veto with prejudice -- declare a bill from Congress so badly constructed that they'll have to get the Supreme Court to declare his opinion of the legal problems incorrect, and then try to get the two-thirds margin vote to pass it.
That, of course, won't really work. Therefore, we need to explicitly give the president the line-item veto. Yes, it would hamstring Congress. That's the point. Make the whole Congress, and the president, carefully review every law that gets passed on the national level.
(This is a pet peeve of mine, I guess.)
Too much of our law doesn't say what it is supposed to say.
And too many bills are a patchwork of laws that may (or may not) actually be necessary and laws that benefit no one but special interest groups, at the detriment of the rest of US. The spaghetti law that results makes it impossible for an ordinary citizen to do anything, bad or good, without tripping over the law.