With the end of the flash season 3 and still some time before we start to get actual details about season 4 I wanted to write about how I would want the general plot of the season to play out. This is all just my opinions and what I would like to really see, I think some could actually happen but some also definitely won't.
After the defeat of a Savitar and Barry being trapped in the Speedforce Wally West has been The Flash now (wearing a new costume, simular to the ginger wallys in rebirth) for 4 months. With the help of Jesse in the field and Cisco, Julian, Joe, and Harry, Team Flash has to stop new metas all over central city who were created by the speedforce storm. Meanwhile in the speedforce we see Barry who is learning more about its presence and talking with the manifestations. Barry then learns that once Savitar went back in time he put another speedster into the speedforce who is revealed to be Max Mecrury. Mecury would then train Barry in the speedforce for his inevitable return as he would get Barry to help him break out of the speed force. Max who knows the most about the speedforce as he's been in there for a century and explains more information about it to Barry telling hm he created it when he got struck by the lightening and needs Barrys help to get out as his speed alone isn't enough. Back in Central City, team flash is struggling getting the new metas of the streets and also have to face old villains who have re appeared and gotten out of iron heights due to the storm such as mirror master and top, the trickster(either one), weather wizard, plunder, mist, tar pit, and others. Back in the speedforce Barry is watching the chaos in central city unfold. As he and the speedforce realize wally isn't fully ready to be the flash yet but shows potential and one day will be. They destroy the speedforce prison so a speedster doesn't always have to be stuck in the speedforce and as Barry's about to leave he gets pulled away by Eobard Thawne. This thawne is the version from LoT who was killed and tries to erase Barry from time as he is already dead and it won't affect him. Barry is then assisted by Mecury, then learns about how thawne still has versions of himself running around time as he created the negative speedforce and that a version of himself will meet Barry in the near future as there destined to be rivals forever. Barry reveals he can't help mecury escape but will brake him out once he gets back to central city. Once Barry returns he fights a version of the rouges who decided to team up as they could rule central city and beat any speedsters together. It is later revealed that the thinker aka Clifford DeVoe has mind controlled the rouges to do his dirty work. Barry then returns to star labs as he with his newfound knowledge of the speedforce and Tracy's knowledge of it find away to get Max out of it.
So these are my ideas pretty much just for the first couple to first half of the season. I think if they were to do this i would wait until the mid season finale to introduce DeVoe but that's just me but what do you think about this?