^There's a huge difference between replacing a few words of ultimately inconsequntial impossible technobabble for something a little more plausible, and making the big changes to the universe you're describing.
Christopher must not have thought it was inconsequential or he wouldn't have changed it.
Norman Spinrad wrote that it was neutronium. Therefore, it's neutronium. Accept it, technobabble some way around it without changing it or simply ignore it. Don't rewrite the past.
What's next, using CGI to replace Shatner, Nimoy and the rest of the cast with Pine, Quinto and the others? Doing so wouldn't change the stories after all.