6. More Jay Garrick
After Earth-1 Harrison Wells turned out to be evil back in season one, Barry has had ample father figures but not one who can really guide him in the ways of the Speed Force. For season three, then, this role will surely by filled by (the real) Jay Garrick – Henry Allen’s doppelganger from Earth-3. They wouldn’t give John Wesley Shipp speed powers again (after his starring role in the 1990s The Flash series) for a brief cameo and then never bring him back.
As Shipp has said, Henry’s role on the show has most likely run its course, so even with Barry’s changing of the timeline we probably won’t be seeing his Earth-1 dad again. But, hey, that’s OK as he’ll no doubt have Garrick around to be the elder statesmen of his four-part speedster gang.
Garrick is also an important member of the Justice Society of America on the comics. Seeing as that team has just been teased on Legends of Tomorrow, Jay could be about to cross over to that show, as well.