To make a real-world comparison, I would say that the Cardassian Union as of 2381 might be compared to the Russian Federation in 2000 upon the ascension of Vladimir Putin: Not back on its feet yet, but on its way.
That's the problem with some novels and incomplete world building, I can't suspend my disbelief. Russia at least has citizens to build with, Cardassia lost over eight hundred million people, and all the allies in the universe can't overcome that deficit.
Saying what if is easy, coming up with a logical basis for what if is difficult.
EDIT: Thinking about Deep Space Nine, I guess they kind of already did this to some extent.
Brit
Listen, you haven't even read the damn things, so I'm not sure how you can just throw that out the window there -- or, for that matter, accuse them of incomplete world-building.
Read
A Stitch in Time by Andrew J. Robinson (yes, THE Andrew J. Robinson). Read
Avatar, Books I & II by S.D. Perry. Read
Gateways: Demons of Air and Darkness by Keith R.A. DeCandido. Read the
Mission: Gamma books by David R. George III, Heather Jarman, Michael A. Martin & Andy Mangels, and Robert Simpson. Read
Unity by S.D. Perry. Read
Cardassia: The Lotus Flower by Una McCormack in
Worlds of Star Trek: Deep Space Nine, Vol. I. Read "The Calling" by Andrew J. Robinson in
Prophecy and Change. Read
Warpath by David Mack and
Fearful Symmetry by Olivia Wood. Read
Articles of the Federation by Keith R.A. DeCandido.
And for historical background, read
Terok Nor: Day of the Vipers by James Swallow,
The Lost Era: The Art of the Impossible by Keith R.A. DeCandido,
Terok Nor: Night of the Wolves and
Terok Nor: Dawn of the Eagles by S.D. Perry and Britta Denison. And then, on top of that, read
Destiny: Mere Mortals by David Mack.
Then, once you've done
all that, then, by all means, accuse Pocket Books of insufficient world-building and of unrealistically depicting the rebuilding of Cardassia. But until then, you are speaking out of ignorance and making inaccurate assumptions about the implications of my comparison.
My comparison was not meant to be exact. Rather, it was meant to suggest an analogy: A former power rebuilding itself, and starting -- starting -- to regain some steam upon the assumption of power by a new leader who is less friendly to the democratic powers.
Let me assure you, Cardassia is still muchly in ruins.
Articles of the Federation, set a year before
Destiny, contains a passage describing much of the planet as being little more than rubble, with orphans living in the streets and a government that's incapable of standing on its own. No one's saying that Cardassia has become a major power again.
What I talked about above was political prestige, and much of it a matter more of force of will from Garak and the new Castellan rather than as a result of any major economic or military recovery.