Eh, honestly I'm not crazy about teen led movies in live action - they always cast too old and it's like a whole bunch of 20-something "teens" usually. I don't mind Nightwing as an adult showing up in the DCEU and getting a film, or any of the Titans characters really - but truth be told for an actual "Teen Titans" movie I'd much prefer to see an animated film than a live action DCEU film. Something more in the vein of Big Hero 6 or Into the Spider-Verse is closer to my ideal TT film than anything the DCEU is going to provide, just because I think animation works better with non-adult characters.
But then, an animated film will never make the big bucks like a live action will, so it'll probably go down with live action first.
(I'm not counting TTG to the Movies because that spun off a show - I'm talking about original films)