I'm curious too, but they did leave the possibility of Rachel being able to help her/bring her back, so maybe it's just more drama for later. Also Garth/aka Aqualad, is he really dead too? Heisn't human, but Atlantean, why do I get the distinct feeling, that he could just as easily have survived and restored by his people and stayed in Atlantis,then brought back to help Rachel get Donna back.
Anyway, even Deathstrokes death seemed a bit vague. A sword goes right through him, but we know he has regenerative powers, or could easily have, which means he can survive, although I don't think heshould be made a major villain at all next season, some sort of frenemy down the line.. I like that they show motives behind both good and bad people, gives a potetnial for either to go eithe way. I also like that Rose, Gar and Connor are restored, they didn't have to do that, Donna going if a bit rushed is a wieghty enough counterpoint, but her coming back would be welcomed rather than mae the Titans feel to over optimistic. Optimism isn't a bad thing, but how you present it makes the difference between a kiddies show and a more realistic adult real life issues and real life presentation I think an element of Titans aims for the 20s/30s age group reality, who would have watched Teen Titans as kids or teens.
Now I'm curious why you think season 2 was much better than season 1. I feel, they work quite well together with the second going into greater depth of the characters and the team, while the first, was an explosive all emergency start with the super powers and creepy death thing as well as a lot of cool, but with theme and substance. I agree with you the endings have been a bit on the weak side, Season 1 ending woul have been perfect with the 2 episodes, Season 2 s ending should have been done in 2 episodes, not 1.