Someone on the STO forums noticed the KDF Mission Journal was in fact now viewable on Tribble (even though the missions listed are not yet unlocked for players); and posted a few screenshots with mission names, etc.
The new journal is on tribble, although you cant play them yet.
there are quite a few new mission and some converted (about 7 cardassian ones and 3 borg).
the new ones make up the tutorial, the stuff on nimbus and some others. obviously we cant tell how long they are so they could range from 45 minute episodes to the smaller 15 min eps that unlock on new romulus.
Not forgetting the Nimbus adventure zone itself, which should have dailys and other open world events, a new FE series after Legacy of Romulus and possibly the ability to team with a Romulan to play their missions if I have read that correctly.