You know, I thought at one time Ziyal might be a good love interest for Jake (I think she was a bit older than him). Frankly, in later seasons, he needed something to do more often than Garak did.
Jake and Ziyal would have been a great couple. You can just imagine how insufferable Dukat would be, thinking he and Sisko having a family bond.
You can count the episodes in S7 Jake appears on one hand pretty much, not exactly what you'd expect from a news service correspondent.
As for him and Mardah, I never saw anything off-putting or weird about that. How many times has an older man in Trek hooked up with a younger woman?