The big one to take on is the commerce clause. I don't know the legalese, but it should be explicitly made a negative power so that the federal government can only use it to stop state laws restricting commerce rather than a positive power they can use to regulate anything that might have a tiny effect on interstate commerce.
For example, let's remove the explanatory clause at the beginning of the second amendment ( A well regulated Militia, being necessary to the security of a free State...) which courts and legislators try to claim is a restrictive clause. Prune it so it can't be a source of confusion.Oh, don't worry. The first and 2nd amendment will be on the agenda for day one. They will try to "prune" them to the point they'll need a stump grinder to eliminate any confusion for the courts.
Be careful what you wish for.