^ Well, my posting (number nine) was an attempt to provide a straight forward response to the OP. The Enterprise D is a superior ship to start with, add the "batmobile armor" to both ships and you essentially change nothing.
Whatever technology the Voyager brought back to Earth at the end of season seven would be distributed to the entire fleet. Remember, Admiral Janeway didn't bring actual physical armor from the future, she brought back information on how to produce it. The same with the weapons, nothing to reverse engineer, the information
Now add the third nacelle to the Enterprise D (which we saw in AGT) and you increase the ship's existing attributes. The OP did not stipulate a similar improvement to the Voyager, which puts the Voyager even farther behind the Enterprise D in terms of abilities.