Not sure if that's realistic. They might add some side content as DLC (the casino?), they will IMO add some end game too and new mechanics. Then they move on to multi player.
I don't expect stuff like missions that were replaced by the Jackie's montage and I don't expect changes to the main story.
So this is my prediction.
You might as well forget about multiplayer and DLC for the foreseeable future. Or any new "content" whatsoever.
If the rumors are true (and there's no reason to believe they aren't given the circumstances), CDPR is hemorrhaging sales revenue in refunds right now. And their first priority is going to be getting the game fixed, stable, and optimized for last gen consoles (this, according to CDPR directly), with the express priority of getting it back onto the PS store. All of which will cost additional resources that were not accounted for before this whole mess. So where is the revenue for their yet-to-be-developed multiplayer game and DLC going to come from?
CDPR themselves announced that ALL plans they remarked on prior to launch are now on hold while they reassess the situation. But the necessary roadmap going forward couldn't be more clear, even to the average person:
debug and optimize the game for ALL platforms
perform whatever tasks are necessary to restore Sony's confidence and get the game back onto the PS store
mechanical gameplay fixes to improve the overall experience (such as NPC A.I. and the like)
And that's just the short-term list. But it's extremely daunting and time consuming. But necessary to rebuild some of the reputation that was sacrificed by releasing this game in it's current state.