I got this idea from a terrific image of impulse with Garrick, Barry & Wally. Essentially I love this idea that Titans (the newly announced teen titans live action) may join the Arrowverse. With Flash exploring the concept of time travel to the future, a perfect Segway to Impulse appears. For those who do not know who Impulse is he is a future descendent of Barry Allen , a speedster, of course named Bart Allen. Anyway.... with season 3 closing and the assumption (a given if you ask me) that Iris will be saved then Barry and Iris' future & descendents will be saved too.
So early on in season 4 ( titans is coming roughly ) Bart allen comes to visit his ansectors and meet team Flash. ( with some great humour, check out young justice's introduction to Impulse for what I mean ) as impulse meeting cisco & HR etc would be so funny. With impulse now a character who wants to stick around or is stuck whatever suits the story. Wally is free to branch off on his own (under used in my opinion at the moment on the flash) to join the titans (drum roll ) Titans joins the arrow verse with dick Grayson and kid flash leading.
With a new younger speedster replacing Wally as a sidekick on flash. Also allowing for amazing crossover ties if Wally & Speedy (Thea), Ragman or Arsenal (Roy) (we can dream) join or at the very least make some regular appearances on titans. (That would completely solidify titans with arrow and flash etc...) and set it in place for arrow verse while yet giving us iconic characters like Dick Grayson (robin or nightwing time (very interested how they approach that) , Starfire & Raven. Especially if the theory (which I completely agree with) that Deathstroke will become the titan's villain after Oliver lets him out to fight Prometheus. Now I have rambled on but I hope this gains some steam and makes its way to someone with some creative influence in DC TV cause it would be awesome in my opinion.