However, I have noticed quite a bit of crossovers with the classes I've played. One of the Consular companion was directly affected by action taken by the Agent, and one of the Agent's companions turns up in the Knight story, for instance. In general there's a lot of NPCs that you run into on one side or another that play a part in other class/faction.
yeah, the crossovers seem to happen mostly in companion convos.
the ones i saw so far were the consular and Qyzen calling Mako to get some help, as well as both Vette and Risha mentioning each other in their convos. apparently, they were both best friends when they were children. i heard that Doc brings Kaliyo onto the knight's ship for something too.