Form is nice.
Try upping the contrast a little ;)

I went through on your advice and tried an abbreviated blue color ramp cribbed from Kaiseto's Snowfall piece. You're right, my piece was too washed out in pastel hues. I was originally using colors based upon Megaman X's ice but With his colors it just plain looks much colder. I think it comes down to that MMX's ice, beautiful as it is, is rapidly formed while moving so reads better light.

For more of a transparent ice look, try adding hints of the back edges showing through. You could suggest the edges either as shadows or as highlights (refraction makes either possible), so try both to see what looks better to you. Your ice looks rather opaque right now without anything showing through it. Example 1, especially visible on the ice cube to the left. Example 2, the 2nd crystal from the left has a really nice back-edge highlight visible. Realistically, crystals refract light in such a way that you don't see distinct back edges, but realistically, ice also doesn't form crystals of the shape you're drawing, so I think in this case it's more important to make it look good and "crystally" rather than realistic.