I finished SSY and I thought it was an excellent story. Actually didn't really feel too much for the characters with the few exceptions being Maria, Maramou and maybe Kiromaru. And that's OK, I don't have to particulary have to identify and/or find the characters to be likable to be a good story. With the exception of the epilouge which I just found to be not believable I really enjoyed it.
The whole lovey-dovey thing I understood. It seemed like the school promoted this kind of behavior and wanted the students to all hook up maybe to relieve stress or something I don't know. Thought it turned out to be a pretty good world building episode after all.
and Spoilers (sorry I don't know how you do spoilers here):
I didn't find Saki to be a sympathetic character at all. Interesting, but not sympathetic. To think she was almost killed by the child murdering psychopaths who run their colony, lost her sister to the same psychopaths, had death sentences put on 2 of her best friends/lover (the people she "most cared about") for the crime of saying that this colony is all f-ed up and had her memories stolen she seemed to be pretty cool with it once it was explained to to her that this all needs to be done because someone went all crazy, not 5 years ago, not even 50 years ago, but 250 years ago! She also apparently kept the secret of the Rats under wraps (unless there is something implied that she didn't) despite having some power given that she was being groomed to be the next leader and helped to save the colony.
Also the epilouge, I can believe that with Saki's help that they would make peace with the Hornet colony. However I don't believe for a second that that the colony would change that fast over the next 10 years or so. It also seem to be implied that they might be killing kids anymore either given that the trickster cats were cute cuddly pets now. Yea right, if anything after almost getting their colony destroyed by a human with cantus they'd double down and be even more paranoid and bloodthristy.