At less than an hour and a half, I feel the movie was too short given the source material and what it was supposed to be. It really wasn't enough time to care about Terra or do enough with the relationships. Like, I know what they're doing with these films, and I know this is probably asking too much, but I can't help feeling that it would have helped if Terra had been more than a post-credits scene in the last one. Honestly, all the villains came across as pretty weak this time around, and I think that's saying something given the villains which have been featured in these DC films -- but that might be putting more expectations on this because of the source material.
Again, because of the time, a lot of things felt way too limited and underdeveloped. Like, they gave a taste of this tension between Nightwing and Starfire in terms of her role as new leader, but that never really had a chance to really manifest; Raven and Robin didn't have a chance to shine (or really do anything..); Beastboy had almost no depth, and I'd say Blue Beetle was the only one who had a successful side plot.