You weren't very good at SC2 then. I am out of practice now, but back then I could beat almost any ship with any other ship, including taking out a Chmmr Avatar with a Pkunk Fury.
While this is true on average, there has been some relatively interesting results lately. The Star Control 2 port named Urquan Masters added internet multiplayer for melee a while back. The result is their forums are full of some interesting ship rankings on which is best. There have even been some pretty good results of redoing the cost of each ship based on how powerful they actually are. Results are pretty surprising.
Just one example of many. This particular one is geared toward veteran arena players, however.