Sounds a bit like what happened with Andrew Robinson, they hired him for what was supposed to be a recurring role, then they didn't bother bringing him back until season 2. Dukat was luckier as he got a scene in Duet, but it is weird that they created these brilliant characters played by great actors and they ignored them for a whole year. But I guess that seeing Bashir possessed by an evil criminal, or having Rumpelstiltskin show up, seemed more important at the time.
In the beginning, they probably meant to treat the majority of the recurring characters like those kinds of characters had been treated on TNG, which meant that they would appear roughly once per season. Thankfully, that didn't happen.