There should be ZERO restrictions on campaign spending and coordination. They violate the 1st Amendment, even when you're running for President.
There are restrictions on coordination for various reasons, but also because a super pac can accept unlimited money while a candidate's campaign cannot. If you allow coordination, the super pac effectively becomes just another component of the candidate's central campaign, at which point financing restrictions / disclosure rules become moot.
Unless of course you are also saying there should be no limits on donations? That opinion among conservative establishment politicians does seem to be en vogue these days - Using the 1st amendment to protect & enable corruption, even as so many conservative
voters stumble over each other to support Trump because he doesn't take said big donations, because they corrupt politicians. Funny how views on the issue have evolved like this!