I think Nolan/Snyder wanted to go for a more serious set of films, pretty much in the spirit of the Nolan Batman trilogy. It's funny but, this all started with Warner Bros. telling Christian Bale to go fuck himself all because they didn't want to pay him what RDJ was making for Iron Man.
The way they handled that entire situation effectively forces Nolan out, since he's not going to work with the studio anymore out of allegiance to Bale... And you're now dealing with Zack Snyder exclusively in Nolan's role -- which is too big a role for Snyder, IMHO... That's what gets you a movie like MoS which, is very similar in tone, messaging and style to The Watchmen. In fact, most people who liked The Watchmen, liked MoS and BvS -- but -- most people didn't like The Watchmen. It was too brooding, with nowhere near enough comic relief (for most people) for a movie meant for general audiences and targeting blockbuster earnings...
If they'd never let go of Bale, they'd have kept Nolan. Batman would've continued on into a new trilogy, Nolan's DC universe would've been more like Frank Miller's and less like Alan Moore's; both very dark, but Miller's far more palatable to most people. That's one of the key tonal differences between Nolan, who I think is phenomenal, and Snyder, who I think is decent.
Now they move forward without anyone steering the ship and Gal Gadot as their lead actor, with the Wonder Woman franchise as their Iron Man....
Frankly, I don't think it'll work; and trying to rely on Gadot and Robbie as headliners seems like rearranging deck chairs on the Titanic.
Personally, I think they should consider a soft-reboot by going back to Nolan and Bale and paying them what it costs to rework the previous DCEU centered around the previous Batman DC Universe... Make a low-budget film with Joseph Gordon Levitt's Nightwing and use that to cut costs for Batman related appearances with Robbie, etc.. Cut the horrible Leto Joker, and try to make the lower-budget Phoenix one work... mesh all the shit together Infinite Crisis style, lol..
Nolan, Bale, Robbie, Gadot, Levitt, Phoenix, Mamoa .. pick a Flash .. and go from there .. Bring in James Gunn to help with Nolan, and bring back Patty Jenkins.. Like, the shit isn't hard.. they could hire these people, it'll just cost money... I dunno why WB has been destroying the DC IP like they've been trying to save pennies on the dollar on actor salaries...