I came into this thinking it would get a bit dark at some point, given Yuno's background and situation.
It's not like there's none of that, but the heavy part to me was the emotional aspect, not as much what actially ends up happening.
I feel like i can emphatize a lot more with Yuno than Reina, on an emotional level. I can understand Reina rationally, though her attitude at times annoyed me a bit.
I think the way things got wrapped up was the healthiest thing they could do, all things considered.