Some of the state courts did voluntarily hold their states to the federal Bill of Rights, nothing wrong with that. In fact I've seen a quote from Madison saying that he hoped it would serve as a guideline.
But to reason that it was meant to require them to do so would be unsupportable. Logically it would lead to the fed courts ruling that it was required- yet not having power to enforce their decision!
All the requirements that the Constitution placed on the states are specifically stated or neccessarily (ha ha) implied by powers given to the feds.
It does seem strange now that the Founders trusted more to their states than the federal government to protect their liberties, but the federal government was new and untried then. It's really surprising that they could have been convinced at the time to give it as much power as they did. It was a near thing! The anti-federalists came within one state of having it all done over again.
The 14th was forced upon us at the point of a gun and has proven a bottomless pandora's box of federal powers.
I would instead enforce section 5 of the 14th - to keep the courts from using it as a blank check. Though on it's face giving the legislature this power seems to be the end of federalism I think the legislature would be more restrained in it's usage than the courts have proven themselves to be.
There is nothing wrong with a Confederation. But since we adopted a Federal Constitution and becamse a Republic, we operate by slightly different rules.