I find that if you write a character well I will care about them. So I like in the DS9 relaunch I came to care about Shar, Ellias, Prynn and so many others. In the TNG relaunch I was heart broken when Choudhury died; I want to know more about all the characters.
I just think Trek is a different beast when it comes to novels. I can read a generic novel and care about what's going on. But when it comes to Trek, I want to read about the characters I've loved for multiple decades now.
For me, a big part of picking up a Trek novel is the nostalgia factor.