I didn't say that everything did revolve around TOS...
Ahem...
Does everything have to revolve around the characters from TOS?
The series is called Vanguard. How many major characters on the station have connections to the Enterprise? With the addition of Marcus and Nogura it's gone up. The Enterprise did their guest shot in the first book. Let the new characters tell their stories.
Look -- it's
Star Trek: Vanguard, not just
Vanguard. It's assumed that if you're interested in reading
Star Trek tie-ins, you want them to, you know, tie in to
Star Trek. If you want fiction that doesn't have any connections
at all to aired
Star Trek, there are thousands and thousands of works of original science fiction that are worth checking out. Try some Asimov or Cherryh or Niven or Benford or Brin or McCaffrey or Egan or Banks or... you name it.
Besides, why are you singling out
Vanguard? Of all the book-only series, it's the one with the fewest central characters from canonical Trek.
New Frontier has Shelby, Selar, Lefler, and Morgan, who's supposedly Number One.
Corps of Engineers has Gomez, Duffy, Stevens, and Scotty.
Titan has Riker, Troi, Tuvok, Melora Pazlar, Alyssa Ogawa, and Sariel Rager. For its first three books, the only
lead character in
Vanguard who wasn't entirely new was M'Benga. Terrell was just a supporting character. Now there's one more lead character, Nogura, with a minimal TOS connection, plus another supporting character, Carol Marcus -- and M'Benga is leaving the series since it's about time for him to transfer to the
Enterprise.
As for Gorkon, it makes perfect sense to focus on the future Chancellor of the Klingon Empire when you're writing about Klingon politics.
Vanguard is meant to be part of the TOS era, to explore the background behind things we saw on TOS and the movies -- things like the Romulan raids in "Balance of Terror," the Klingon conflict in "Errand of Mercy," the backstory of Dr. M'Benga, the development of the Genesis Device, and so on. VNG was never intended to be totally unconnected from TOS; it was
meant to show us the larger stories behind things from TOS. So naturally there are going to be connections.
Of course, this is just my opinion. I'm not saying the authors did or are doing a bad job. There's just some things that pull me out of a story. Having the universe feel like it has 1000 people in it is one.
I'm no great fan of Small Universe Syndrome myself, but I don't think it's anywhere near accurate to hold up
Vanguard as the poster child for it. On the contrary, VNG is one of the most successful series at balancing familiar characters and concepts with new ones and making the connections seem logical rather than gratuitous.