Granted, still with a grain of salt like the rumors about a month ago, but apparentally this would've involved:

-The film starting with Kylo Ren attempting a galaxywide communications blackout to keep the Resistance in check
-Luke continuing to train Rey as a ghost but also causing problems for Ren (Keeping to his TLJ speech "See you around, kid" "Strike me down and I'll always be with you" etc).
-The movie opening with them capturing a Star Destroyer, with Rose heavily involved
-Visits to Coruscant and Mortis
-Darth Plageuis shows up instead of Palpatine, but is known by Tor Valum, not Hugo Damask as the EU made him.