I agree that the relationship between Ghemor and Kira in "Ties of Blood and Water" is stronger relationship than seen at the end of "Second Skin", but it has been a while. Maybe they stayed in touch and developed the relationship more since last time we saw them together. "Off-screen" solution to inconsistency.
I find the Cardassian politics interesting. Ghemor was a big part of the Cardassian dissident movement. So when the dissident movement took over Cardassia in the form of the Detapa Council in early season 4, certainly Ghemor was a high-level person in the government. The same government Dukat sided with in "Way of the Warrior". And the same government Dukat overthrew in "By Inferno's Light". You can see how these men have an interesting history. And I do love seeing Dukat (and Weyoun!!) on screen.
Plus we see the old Cardassian custom of revealing all your secrets about your enemies to your family when you near death (Shri-tal). Last seen when Tain talked to his son Garak right before dying in "In Purgatory's Shadow".
While I do feel that the parellels between Ghemor's death and Kira's father were a bit forced, I did like seeing the flash-backs into Kira's life. And it was nice to see Furel again, even though he died in "The Darkness and the Light".
By the way, according to the book "Fearful Symmetry", Dukat did know where Ghemor's daughter was at this time. But he never would have revealed her to Ghemor because he had been treating her so badly.