In the past couple days it has been mentioned in a couple threads that Titan appears to be the only ongoing Lit only series(DTI has only been 2 books, so I don't think we can call it ongoing yet), and personally I'm really disappointed by that. I think we've gotten some great stuff in the Lit original series, and really hope that is not coming to an end. I know that the books based on the TV/movie series have a lot more freedom now than they did a decade ago, but there is still a certain amount of freedom that the authors were able to have with the completely original characters that will be missed. If weren't for the Lit series we wouldn't have gotten characters like Mac Calhoun or Dr. Ree, who I would put right up there with Spock, or Data as great Trek characters. If the era of Lit original series is over, then I will miss it.
I do really want to see a new novel series as well. I am hoping that Rise Of The Federation could be a new series, since it's set in the most interesting era I could think of right now. The 24th century is being well catered, as is the 23rd. Stories about the actual founding of the Federation, the creation of the final frontier, is what I'd love to see. And in a way like Vanguard was handled. Not just one ship out there. We could have intertwining stories through all the books, some political, some about exploring, but all about how the Federation was actually created.
Looks that way, especially since it features series regulars from 2 Star Trek series (TNG for Riker and Troi, and Voyager for Tuvok), and the TV series books are currently the only ones being added too.
I suspect that "The Fall" will wrap up most of the 24th century's ongoing plot threads and set up the next phase of Trek lit. It'll be after that, in 2014, that any new series' may start.
Does 'Typhon Pact' count as a Trek Lit series? It certainly didn't exist in the TV shows. I'm hoping to see more Corps of Engineers at one point.
It might be that Titan will get a reprieve from the shuttering so many other lines have gone through (or seem to be going through) because of the central place that it played in Destiny, which was a big hit, as well as utilizing several "main" characters from TNG and Voyager.