Since each level of the Steam badges are an upgrade level, tiers 1-4 aren't too appealing compared to the final versions. I adore this game, but have no interested in obtaining badges.
Given the love that people have for the insects in the game, I think people would enjoy badges much more and would be far more involved in market and trade forum if each tier was a different bug. Aphid, gnat and weevil are the obvious ones, and there are plenty of others I think people would like. So many, in fact, that maybe it would be fun to have a poll that allowed players to vote for which bugs would be represented by a badge.
I don't know if it's even possible to do this now, but it sure would be awesome.