I'm fine with them using the more classic roster. Though the tone from the small amount of detail given does remind me of the animated series some, but that isn't a bad thing. I get why people wanted Cyborg but I'd rather see him in a Titans movie if I had to choose. Though just because he might not be a main character in the movie doesn't mean they can't involve him somehow. Like have Vic be the son, or relative, of Amanda Waller and introduce him to the audience that way setting up something down the line. Just simplify the connections some and also setting up the ground work for a potential Titans movie through upcoming movies.
I mean I hope they plan ahead and have future movies and movie series in store for this universe they are creating. Introduce Vic/Cyborg in the JL movie, introduce Wally in the upcoming Flash movie, and have Robin already active in the new Batman one. Having a Batman and Robin film would easily set it apart from the Nolan movies, so they don't have to copy/paste what he did, and with that you can start creating buzz for what they could potentially do in the future. Probably not going to happen, but just a thought.