How about paying $60 for Omega only content? That was basically Force Unleased 2, which took me 4.5 hours to beat.
Its hard to compare the value of DLC. Some only last 45min like the Harvey's Revenge DLC for Arkham City. Others can last as long as single-player FPS games like the DLC for Bordlerands 2.
In the Mass Effect realm, I didn't find any of the ME1 DLC to be meaningful or "worth it".
In ME2, Overlord and LotSB were both excellent pieces of DLC that should be the gold standard of DLC. While neither ultimately affected the game or ending, both served as fantastic short stories that I wanted to immediately replay. Kasumi was fun, but a little shoe-horned in (especially in a game where a lot of the immersion revolves around companions interacting).
In ME3, I begrudingly bought From Ashes. It sucked to pay for Day 1 DLC, but objectively the content was awesome and felt like it was a part of the game and not a seperate side mission (which further annoyed me since it was Day 1 DLC). My disappoint with the ending and Bioware as a company has prevented me from purchasing either Leviathan or Omega. However, I think $15 is a bit high price-point for a DLC unless it contains multiple DLC content.