Unlike a lot of members of this site, I do not want to see DC's TV and cinematic universes merge into one. One reason being that I'm just about positive that they did not plan ahead on this, meaning it will most likely leave massive plot holes in the combined universe. The second reason is that with two separate universes, there would be less restrictions far as what they can do and who they can use. With that being said, I have some ideas on what I'd like them to do with their CW shows.
A Teen Titans show with Robin/Tim Drake(if rumors and speculations are right Dick Grayson is already Nightwing and Jason Todd is already Red Hood and I think a current Robin should lead the team), Beastboy, Cyborg, Raven, and bring in Starfire later in the show. Cyborg will be introduced in the Flash show; he was meeting his dad, while he was working on the particle accelerator and got stuck in room when it exploded. His father keeps saves him by giving him mechanical body parts. Beastboy's origin will also be tied to the particle accelerator; his mother brings Garfield back from Africa, after getting a rare disease. While being treated he's exposed to radiation coming from the explosion, which rewrites his DNA, making him Beastboy. Raven's origin will be the same, but she will be underground, no one knows about her and her powers until the pilot episode. Reason for Starfire coming in later within the season is to keep the introduction to super powered beings in the universe being all after the particle accelerator incident(with the exception of Slade, Roy, and Cyrus Gold). In the first season Starfire will leave the Teen Titans at the same time Roy leaves Team Arrow in the corresponding season(I'll go into why later, if you haven't already figured it out). In later seasons, more heroes can be introduced.
After Teen Titans first season, I would create a Red Hood and the Outlaws show. With both Roy and Starfire leaving their teams, they join up with Jason Todd/Red Hood to help him go after The Untitle.
At some point in the Flash series, I would give Wally West his powers, making him Kid Flash. Barry mentors him, but later in the show realizes he'd be better off with the Titans.
Now the big one, a Justice league show, with Nightwing, Green Arrow, Black Canary The Flash, and Green Lantern. We know for sure we have Green Arrow, Black Canary, and The Flash; Nightwing is rumored to appear in Arrow, and Green Lantern is rumored for The Flash.
That's all I've got so far, but what do you think? Would you like to see this done? let me know below.