Well, the short clip is making me want to repeat listen to it, which is a positive sign. Intro sounds good, Hikaru's part sounds okay, but very generic, sadly. When it changes up a little at around 30 seconds I start to like it a lot more. Where's all the Keiko at, though? Good to hear a lot more from Hikaru though, and she does a good job. The 'heavenly bluueeeee' bit at the end bugs me a little, but hey. I guess I'll wait for the full song, but I'm pleasantly surprised. Maybe it's just because I had very little expectations for it.
Then again, after watching the whole of Animelo 2014 with a friend I actually warmed up a little to Heavenly Blue, and I never expected that to happen.