They have no professional experience with Trek (which imo is a good thing, we need some fresh blood).
As fans of the series, the three main creative minds behind the film, JJ Abrams, Alex Kurtzman and Roberto Orci are a nice mix.
According to Abrams, he is a geek and a HUGE fan of the original series but he's a lapsed fan. He seemed familiar with TNG, a little less of DS9 and then almost no familiarity after that.
He said he had not seen Nemesis at all for example. He did say he would watch EVERYTHING in his preparation for the movies however.
Kurtzman is described as being an enormous fan with an encyclopedic knowledge of Trek, not only all the series and movies but even the novels.
And then Orci is described as a complete noob to Trek.
So basically, they have the committed fan, the lapsed fan and the sci-fi fan who never got into the show for whatever reason.
A fairly nice mix.
Also, if you read on the process Mission Impossible III went through (a film directed by Abrams and written by Kirtzman and Orci), Abrams sold Cruise on the idea of bringing in his two handpicked writers to redo the script in order to make it CLOSER to the spirit of the TV show.
Again, I consider this a good sign.