I can't see why they can't have c or d level subplots that could give something of an 'arc'. They could be self contained in each novel so that they don't 'put off' casual readers but still fit together to give some continuity and development between books...
Possibly. It's tricky, of course, in that the future of the 23rd Century and Kirk's crew is already written in stone (in this timeline at least), as opposed to the 24th century which was left more open-ended when the shows went off the air.
We already know what's going to happen to Kirk and Spock and the Klingon Empire and whatever between now and the Next Generation, so you can't really have any sweeping changes to the core characters and situations. It's not like we can give Sulu his own ship or blow up Romulus until . . . well, you know.