So, I confess I haven't heard Storm before, so I listened to it today.
It's... actually pretty good! Not a lot of range compared to FJ's usual songs, but it's got a great melody and rhythm. I can see it working. (As a side note, Ami Koshimizu sounds like a decent singer. Not impressive, but very pleasant).
The major downside I'm seeing: this song seems tailor-made for a Kaori verse + Wakana refrain + Yuriko background vocals combo. That wouldn't be a problem...
if it weren't the combo for every other song! It's possible it'll be Keiko verse + Wakana refrain... but that's still not very innovative.
I'm praying for more vocal switches. Keiko and Kaori alternating on the verses, Yuriko, Kaori, and Wakana alternating on the chorus... or maybe that'll sound too chaotic.
Btw, who sang the background vocals in the original? Maybe it'll be a good idea to put Wakana on those, and have Kaori and Yuriko alternating on the choruses.