I'd like to see them in the Federation, as commentators on the smug self-assurance of the Feds, even as they find that the values held by those obnoxious humans, Vulcans, and so forth are actually their own. I'd like to see a Cardassia that's on the brink of realizing they need not be "conservative" in order to prosper--that they need not be afraid in order to survive.
Yet you so perfectly illustrate my point as to why they need to be outside the Federation as a strong competitor.
That you cannot accept the existence of conservatism as a legitimate alternative view even if you do not agree with it--that you look at it simplistically as though all conservatism is is fear so that you can dismiss having to consider or even just put up with its existence without automatically sneering at it...that right there is exactly why the Federation needs a kick in the self-righteousness. You seem to assume that the only people whose views are worth having are those who adhere to the exact set of liberal/relativistic values that the Federation have, and that the only way in which a society can grow and develop in a positive way is in the direction YOU favor. That is simply not true...and why a real competitor needs to be around.
Now, IF we are talking about the pre-war Cardassian system, fascist regime and all, yes--you would have a point about the role of fear. But I am talking about post-war, doing away with the totalitarianism and leaving the positive values...and the capacity to believe strongly
in them and not be afraid of that passion...intact.