I didn't like how the Romulan War books went out of their way to explain design changes as tech changes. I can totally believe TOS is more advanced than Enterprise even if it doesn't look more advanced to us. It's all pretend anyway, just design work. I trust Christopher to merge the two periods in a more nuanced way rather than trying to undo Enterprise.
On topic, this book sounds awesome. I've never loved the show, but a lot of that was from them telling stories that didn't feel right to the time. Some elements like the conflict with the Vulcans were great and made the period unique. Too bad there were big ideas like the Xindi that felt like 24th century ideas.