What difference does it make whether you pay $30 for one expansion or $10 each for 3 DLCs?
Expansion packs usually contain enough content to justify the price tag. DLC is usually shit that should've been in the game in the first place just cut out and sold later.
Example:
Call of Duty 1: 50$ for the core game + 30$ for UO expansion pack.
MW2: 60$ + 15$ Map pack x2.
Who's to say the games aren't finished? The episodes are a segue between HL2 and HL3, not full fledged sequels, expansions, or patches that were missing. They're important to the story but don't need more than a few hours to tell.
Hl2 was too damn short for 50$. It felt more like half a game. If valve made Hl2 longer by adding the episodic content in it I would've loved it.
DLC gives the developers the ability to expand on a story or a scenario with ideas that might be good, just short. That's all it is to me, I can't fault them for having ideas after the fact.
DLC is a good way for developers to justify screwing the customer. I'm not paying 10$ for another hour of playtime. I've spent nearly a grand on DLC for my PC, 360, and PS3. Most of it was not worth it the asking price.
The only good DLC I bought was Dead Money for New Vegas. The FO3 DLC is just terrible. Operation: Anchorage and Broken Steel should've been included in the core game. They felt deliberately cut out. Point Lookout was not worth the 15$, The Pitt was decent, and Mothership Zeta was okay.
I'm not against DLC. I'm against developers using DLC. Episodic Content and Expansion Packs as a way to charge the customer for the same game twice.