On WoW:
Each expansion has increased the level cap by 10, adds a whole new continent (the game shipped with two, that's nothing to laugh at), added some game-changing element (TBC added flying mounts and heroic dungeons, WotLK added vehicles and revolutionized questing), added a PvP battleground (a new one is coming out next content patch, as well), and several new spells for each class (and often in doing so completely changing class mechanics). And, in WotLK's case, adding a whole new class. They can only add more dungeons for so long before they have to extend the level cap and add new areas; eight tiers of raid advancement would be ridiculous to pack into the space that shipped with WoW. The expansions are completely worth it, if not necessary to have been made. And before any of you bash the game's quality... I think the 11 million active subscriptions speak for themselves. To surmise, a Sims expansion pack or stuff pack does not revolutionize the gameplay as a WoW expansion does. Plus there's plenty of content patches in between to sate the appetite for new things to do, and all the while the developers' passion and dedication shines through. Blizzard is a rare case where their success has been well earned; they make their games because they love to, and not specifically for the purpose of appealing to a mass-market.
On StarCraft 2:
SC and BW had three campaigns, and around 30 missions each. SC2: Wings of Liberty (the first one) will have around 30 missions total, and the two to follow it will be the same length and add content (i.e. new units), so I don't see what there is to complain about. Essentially, they're saying that they're not making any single player content for the Zerg or Protoss until they've got the main game out the door, and that they're going to focus on one race at a time in their expansions. Would you have complained about Brood War if it was the second in a StarCraft trilogy, and its campaign was Zerg-only? And despite what anyone may say, this decision was supposed to have been due to Blizzard not wanting to compress their planned story arc into one 30 mission campaign, and knowing their developers' passion for their games, I believe them. There's also no confirmation that Heart of the Swarm or Legacy of the Void will cost as much as the first act of SC2.
On TS2:
The Sims 2 was great for a long time. Expansions were a large part of what made TS1 fun and unique. I won't deny that they improve the game and add depth. However, EA clearly ran out of ideas and started doing it just for the money and not to expand on the game. I have a hard time believing Pets and Seasons were copouts for cash - they added a great deal of realism and gameplay that The Sims had been devoid of - and most of the others were decent. But Free Time... really? As if my Sims weren't busy enough already? Like they needed hobbies? Which, by the way, cramp the wants section and in doing so end up taking over their lives if you want them to have decent aspiration levels. And Apartment Life is just plain stupid. Oh, yay, I can put them in tiny houses! I also don't approve of the half-assed attempt at recreating TS1's Makin' Magic that was thrown in, which was possibly the most fun of TS1's expansions. And this was after they started making Stuff Packs, which I see as an attempt to tap into the success of TS1's most essential expanion, Livin' Large. I can understand if they were completely original items with new uses, or better than what you could get with TS2 or expansions, but no. They're just themed packs of furniture and decor which could have easily been thrown in with the expansions (as they were in TS1). Note that Free Time and Apartment Life were both developed after EA bought Maxis.
On Spore:
The simplification and kiddie-fication of Spore aside (which Will Wright, the father of The Sims and Spore, disapproved of, and was done entirely because of EA) I don't see EA diverting from the formula that sold 100,000,000 units of TS2 and its various expansions and stuff packs. However, despite all of this, I do think it's a great game... albeit not as good as what was originally shown at GDC '05 - the Spore that was Will Wright's vision. When I get around to getting the parts pack and Galactic Adventures (which I will, when I next revisit it), I don't plan on paying for them. EA can get by without another $50, and Spore should continue to be an example of the futility of DRM.
TL;DR:
Yes, Spore is turning into "the next TS2." Long live piracy!