According to what's been said, there's going to be faction specific stories (suggesting class stories) as well as planet stories and heroics for Makeb and the 5 new levels we'll be getting
As we saw with the convo's for HK-51 (and his unique reactions to each class and species - check 'em out on YouTube, really a blast. Over 16/17 minutes of convo for the Republic classes and 16/18 minutes of convo for the Imperials, depending) they still have the voice actors and the writing skill to do these kinds of missions. I think we'll be getting a full set of post-Illum class stories
Ater all... it IS called Chapter 4. And if the chapter is the same for every single class, then it isn't REALLY a new chapter - is it?
Not really, faction stories just suggests separate story lines for Imperial and Republic on the planet not one for each class, also:
Story content in the new expansion | 12.18.2012, 09:14 PM
Hi everyone - I asked Jeff Hickman for some clarification for you on whether Makeb will feature an extension of class stories. Here's the info:
"The intent for Rise of the Hutt Cartel is to continue your character's story, but envisioned as part of the ongoing struggle of the Empire vs. the Republic. There are lots of great moments for you to enjoy, and it will be shared as two clear storylines. No class specific storylines are included, though I know you guys are going to love what RotHC has to offer."
We hope this helps clarify!
That's in the dev tracker.