As an Ohioan, I oppose any change that would more closely tie us with Michigan, including eliminating the state borders. We fought a spirited war over Toledo to establish that border! And the Ohio River forms the southern border. Says who they're arbitrary?
I think that debunks points 1 - 3, at least from Ohio's perspective. Point 4 seems to debunk itself, with the supreme productivity of the House in recent years.
I do not think the problem is with the Constitution, but instead in lack of following it, and in the people who are in the government (particularly elected officials). The Constitution is, after all, one of the oldest still-in-effect governing documents in the world, and has been largely effective.
If we are going to do away with it, how about doing away with the federation as opposed to the states? Sure, we can still have an Articles of Confederation for a few things like maintaining navy, establishing tariffs, and interstate transportation projects, but on everything else let the states take care of it. It could have some benefits, such as less polarized politics and less militaristic foreign policy.
Not that I'm seriously suggesting doing away with or restructuring the federal government, but I'd sooner start there than states in terms of something to reform (although that might be different depending on the state I lived in).