Some very nice info can be gained from them:

Nothing special, as expected, 20 is dominant value, with the many 0s attributable to land maps.

This is area actually, not size, but the root of it shows a pretty even distribution from small to large. Area is map height*width in spring units.

Wow, there is hardly any variation of gravity in the mainstream, with mostly speed maps providing the low gravity environments.

A closely gaussian distribution! Can it be that spring mappers, as a collective, have stumbled on a great way to vary gameplay?
This graph gets even better with wind values culled to 25 (the max in *a mods):

If you want it, I can post the spreadsheet of my data.