My problem is why announce a big slate? DC's problem has been universe building. Marvel didn't come out and pre-announce Iron Man, Captain America, Thor, and the Avengers before any hit the screen. The made one, then built on it. No seems to want to actually build or earn their universe, they just want to start with it. That's where they fail.
The last DCEU started after MoS and Avengers. There was no 'universe' plan until Avengers hit, then they jumped right to it and it wasn't any good. Hell, the Ghostbusters with the women wasn't even just a movie, it was supposed to be a universe, too. With multiple movies, cartoons, games, etc and they touted it when they announced the first movie...one movie, bombed, no universe.
Not to mention, DC is the group that blocked certain characters on the CW going back to the WB. Clark could never BE superman...they could never use batman, etc. Why? Because they didn't want people confused as to why there were multiples. Now? You WILL still have people confused as to why Henry Cavil isn't Superman, why Affleck or Pattinson aren't Batman, why is Momoa playing someone else (if he plays someone else), why are there two (or possibly 3) jokers?
What happens if the 'new' Superman bombs massively? Do you keep going since you announced several things? or do you scrap it and start over?
I don't know, the proof is in the pudding as they say and we won't know anything til they start making stuff, but nothing about the slate sound exciting or interesting. But, then again, when i first heard about GotG i thought similarly until the trailer hit. I guess we'll see.