"I can rationally see that there could be a lot of uses for it, in fact, in modernizing investigations and law enforcement."

In other words, you feel that these people do not have enough power over the public, and should be given more:

https://en.wikipedia.org/wiki/File:San_Bernardino_police_swa...

"Presuming that it has appropriate checks and balances"

It will almost certainly not, except under the most far-right definition of "appropriate."

"with every plate-holder having the right to use that same information themselves"

Have you ever tried to file a FOIA request? The public will have a substantially harder time accessing that information than the government will.