They made it almost seem too unbelievable when we meet Cardassians for the first time, too. A single Nebula class ship takes out several Galor class warships, and we're supposed to believe that there's been a war going on for the past few years? The Cardassians were made to seem way
too weak in their first introduction. They remedied that a bit in DS9, but they still seemed to favour showing the Federation as having markedly superior technology.