Another of the many reasons this Universe was always doomed to fail was its pacing. Not the well publicised issues with the films but rather the release schedule of the films.
This universe is now 5 years old had we’ve ‘only’ had 5 films. During those 5 films we had a 3 year gap between MoS and BvS which gives the impression that this wasn’t planned at all but rather a reaction,
Compare that with Marvel who did the below in their first 5 years
Iron Man 2008
Incredible Hulk 2008
Iron Man 2 2010
Captain America 2011
Thor 2011
Avengers 2012
Iron Man 3 2013
Thor 2 2013
With that you get the clear impression they wanted to first establish the key 3 Avengers first and then expanding into the niche characters (GOTG, Doctor Strange etc).
So far with the DCEU, Batman hasn’t had his own film, Superman is still waiting for his own sequel, the Flash hasn’t had his own film yet they’ve all featured sporadically in 3/4 films. Films like Suicide Squad and Shazam arriving ahead of the aforementioned is just bizarre.