They could do worse than to look at the ship designs in BOTF. There were cruisers of various sizes but also small destroyers, similar to those seen in "Sacrifice of Angels". (Look a bit like those weird fossils) Also their hulls tended to be stronger and their shields weaker than average.
As far as the Cardassians as a people go... welll we know that prior to STO they had a massive military budget which accounts for the strength of their military. Also the Obsidian Order is more than capable of influencing military events through sabotage and espionage. They don't just interrogate, the also assassinate.
And let us not forget that Cardassia definately does have scientists, 2 of them appear on DS9 early on. But I believe they themselves said that science is a low priority for Cardassia.
I dont think they should be better engineers though as according to one of the scientists MEN dont usually make good engineers. So unless you are playing a female Cardassian your engineering will suck!