The weird thing isn't that she was written out. But that she was kept alive and everybody acted like she was dead for the rest of the show.
Very true. Kira could have visited her to share news and her frustrations about Kai Winn and the dominion. Then, Kira could have been killed and brought back to life while down there. Now she's trapped, too. When Kira doesn't return to the station, the crew fears the worst. Garak, who happens to be around when they are discussing this suggests a gas called trilerium that the Cardassians have been experimenting with which blocks outside sensors when released in large quantities in the upper atmosphere of M Class planets. They could use this gas to temporarily block the orbiting satellites (he is "unable" to share why he knows this information or why the Cardassians need such a gas, but Garak does think he can get his hands on some of it). Bashir jumps in and says they can simultaneously flood the lower atmosphere with antibions. The combination of these two in the atmosphere would theoretically neutralize the biomechanical devices. The theory is the people on the planet surface will survive, but it's just a theory so there's no way of knowing for sure without trying it. So they take a runabout to the planet and try it while in orbit, everything appears to work as planned, but then unfortunately everybody dies...except for Kira. After several tests back at DS9, we learn that Kira has a small trace of toxins in her system which helped her survive. According to Bashir and Garak, Cardassians are the only known species with this specific toxin naturally in their systems. Bashir never detected it before because it's not something that comes up with standard tests. Kira has an orb experience featuring Opaka. Opaka says "Kira is not of Bajor." Kira is left with more questions than answers. The episode ends.
LOL...but seriously, I would have loved to see Kira visit Opaka once or twice at the very least. I liked Opaka.