At this point, here's what we know. Gabi is recast, Harris is leaving in June/July, and a big scandal is going to rock Salem to its core. There are two major storylines with this potential, the drug arc and Victor's long lost son arc.
What could happen:
*Konstantin could reveal the truth to save himself or Theresa will slip up due to negligence or guilty conscience because of how Alex is treating Justin.
**When Xander finds out, all three get the works from him, Maggie, Justin and everyone else. Alex still behaving the way he does will make him look bad either way
*Lucas and Harris uncover the drug ring and Ava and Stefan come clean about Clyde.
**EJ might get in some trouble because Stefan or even EJ himself will reveal his knowledge of his brother's involvement and Mayor Paulina will consider firing him, especially for what he's doing to Tate
*Gabi's return could mean a return to her case where is proven innocent in Li's death.
**Two ways it could play out: First, Li could've faked his death with Rolf's help to punish Gabi. He overconfidently thinks EJ will help his endeavor of revenge, but to save face from the drug fiasco, he'll rat him out to free Gabi, if only to save his job.
**Li is actually dead. Perhaps Clyde want him to do the drug pushing but turns him down. Is stabbed but overhears the plot to frame Gabi and before he died, he tries to warn Tripp and Wendy but succumbs to his injures
**Or it's a mix of both and is just off on an island somewhere. It's a soap after all.
*Baby Jude will reunite with Nicole after Sloan gives into her guilt or another DNA test is done. EJ read the results in the safe and learns of Jude's parentage. He'll keep it to himself to salvage his relationship with Nicole and keep Eric away since he sees their connection is still strong. In time, Eric will find out that Jude's his. But it might not be until close to the Holidays. I see this arc being the one to drag out that far.
*Abe's memory will finally return as Paulina gets more sick. His worry and concern fills in the gaps in his memory due to be in a similar situation when Colin had him and Paulina hostage. Whether Paulina will live depends on the next direction of her story.
*John's pawn status is reactivated and more of his past is uncovered due to Konstantin knowing John from a point in his own past. Diane Colville might hold the key to this arc because she's back too. Leo playing a role is 50/50. But if he turns out to be John's son, he might use it as an excuse to integrate himself into the family for con purposes...or perhaps this might what makes his heart grow three sizes by Christmas.
**Steve and Marlena might work together to reprogram John.
What I would want to happen on the show (thought it might not happen this year or for the forseeable future)
*Rachel realizing how dangerous her mother is.
*Orpheus returning and forcing Salem to look for his son and grandson after Jan Spears made them disappear.
*Bo waking up and forgiving Shawn for shooting him while also coming to terms with Victor's death as well as his mother's death since she died while he was frozen by Megan and Rolf.
*An arc where Philip's son Tyler, whom he gave up for adoption, returns to Salem to claim his Kiriakis birthright or just to find him.
*An arc where J.T. Reiber, Zack Brady's doppelganger, from a previous baby switch story, returns to inquire about Rolf, his maternal great uncle. Also, if he is just as smart as Rolf, it would be nice have a scientific battle of wits between the two.
That's about it for now.