I imagine that would be soon after Deep Space Nine ended, since it was only Ben Cisko who stopped them joining in the first place.
This poll is interesting, the rumours were saying that the new series is set after Star Trek 6, but no one voted on that option yet
There's 3 "Other" votes which haven't been commented for, I'd like to know which periods they are, Khan on Earth or other pre Enterprise? Mirror or Negative Universe? Same timeframe as any of the current series? Further into the future where timeships are used? What ever it is please leave a comment.
Sisko.
Of course, in the post-TV books, Bajor has been in the Federation for about 10 years, and a Bajoran even became president temporarily.
I'm honestly not sure when I'd like a new Trek to be set. To be quite frank, I'd probably just enjoy them taking the books and dramatising them. The writers have significantly expanded the Trek verse since the TV shows went off air, with the books now something like 10-20 years beyond the end of the TV shows. More to the point, they've brought in a recurring cast of political characters, beginning (well, more or less) with Keith RA deCandido's The Trek Wing, Articles of the Federation. That has allowed the books to tell a much bigger story than "ship goes to planet, gets in trouble, find a way out, go home".
Of course the best Trek book is Christopher L Bennett's "Watching the Clock", showing the work of the Department of Temporal Investigations.