Nah. The cinematic universe and series universe are way too different and while the series actors are better for their dramatic and constantly emotionally testing situations, they wouldnt suit the cinematic universe.
The actors in the tv series are terrible... Don't get me wrong, I love and enjoy all these shows, but the acting is cringeworthy and overdramatic. That could also be at fault of the cheesy scripts they have to follow. That's why they're on TV and not in movies. Also, the shows are NOTHING like the original adaptations in the comics/movies. They make too many changes to make the show enjoyanle to a larger audience.
I was thinking about this earlier. I think they don't cast the same characters because then the story from the series would have to be cannon for the movies & vice versa. For instance since the Flash & Green Arrow have already taken on multiple bad guys, the cinematic universe would have to get those same actors and use the same character arcs as in the show. It's easier to make it a different universe entirely and not have to worry about messing something up. Besides, the Flash in the series would fuck everything up for everybody since he's always doing dumb shit with time.
The is a reason why the actors stay in the small screen. They simply aren't as bankable as the Hollywood A-listers on the silver screen. In comparison, TV actors lacked box office charm to make the tickets sell.
It would be like saying the same to Marvel about any characters that are in both X men and the avengers to just have the same actors. It would make no sense as the storylines would clash and make it impossible to keep up with what was going on
I mean, Ezra Miller seems pretty good as the Flash, but what the fuck DC?! You've already cast him, why not use him again??