I have no idea what this means, but I'm also completely illiterate in US political theory. Is your point that republic implies strong federalism and democratic does not?
To understand how the US government works it is very similar to the UK under Oliver Cromwell prior to the attempted creation of the third house, it was basically modeled after that period of UK government.
Personally I like the idea of devolving authority away from the Federal side and towards the States but honestly it's a giant rat hole that mixes power politics (something Americans do well enough with) and history (something that Americans do not do so well with).
In any case more centralized or less centralized is the work of decades not years so I would hope no one is holding their breath in any direction.
This is, in essence, a substantial portion of what is asserted in The Federalist Papers, an 85-part series of letters and treatises written and distributed in 1788 by three proponents of adoption of the US Constitution.