I think that Section 4 should include the option for state lawmakers to impeach both president AND members of Congress if Congress doesn't act 30 days after the president doesn't act. (Speaking of which, I'd like to see a provision which repeals 16th and 17th Amendments.)
Also, for appropriation bills initiated by the House of Representatives, the proposed Balance Budget amendment need to incorporate wording from attempted enumerated powers acts into bill, requiring Congress to cite specific constitutional clauses in any appropriations bill which reasonably justify each appropriation under Congress's constitutional Article I, Section 8-limited powers.
Also, the amendment needs to make clear that Senate majority leader will tried for treason if Senate guts a House appropriations bill and replaces contents with appropriations legislation, as Obamacare Democratcare bill allegedly was, as Clause 1 of Section 7 of Article I prohibits the Senate from initiating such bills.
My understanding is that the Goldwater BBA legislation is written in a deliberately narrow fashion so as to present one single subject, as some constitutional scholars have recommended. Besides the fear of a "runaway" convention, the most common argument against the broader CoS that I hear is this single-subject rule.
Personally, I'm not smart enough to know who's right, but I do know that the Bill of Rights sure wasn't a single subject, and all ten of those amendments were the result of a single call for a convention of states to amend the brand new Constitution.
Well, with any luck at all, we'll see soon enough!