Sadly, I suspect that anything that contains indisputably happy endings for a majority of the characters is "too sweet" by the standards of today's audience.

There is a strong tendency in SF/F fandom today to value the grimdark. No character can be allowed to be wholly or even mostly noble; no one ever simply processes and gets over a trauma. (Of course, no one is allowed to find actual satisfaction in revenge either; the avenger simply *has* to fall into despondency on realizing they no longer have a reason for living.)