Boomer has barely even been in the series since "Rapture", while Starbuck got the entire Demetrius storyline pretty much to herself. She doesn't lack airtime.
Yeah, but I'm not sure Boomer really deserves
an entire episode. I mean, it's not like she's critical to the story...
Clearly, the producers agree with you. I can't fathom why such an interesting character - a Cylon who thought she was a human, and was basically forced by other Cylons into an evil zombie mode into which she was murderous - has never been deserving of a decent storyline, once Athena took her place on board. Boomer should have had deep issues with the other Cylons and an entirely different worldview, but this was shown only in "Downloaded" and the character was dropped after that. Instead, the BSG producers apparently prefer manufactured drame like the Sam-Kara-Lee-Dee quadrangle of doom, or the Ellen-Caprica-Tigh shit from last week. They could have a really dramatic figure in a Cylon who loathes what the others did and is hated by the humans for all the wrong reasons, but it just didn't interest the producers. A pity.