No free wing with Blackrock Mountain at launch confirmed

There's actually not a single part of your analogy that has any relevance to the topic at hand. I'm impressed. So in your analogy, power windows is supposed to be the Undertaker I assume? Well let's start from the beginning:

if you bought a car that was advertised as having power windows

Okay, judging by the OP post, he bought Naxx fairly close to the time of Undertaker nerf, so I guess he had heard all about how cancerously OP it was and he was REALLY excited to finally get his hands on it and make his first cancer hunter deck! But, last time I checked, this wasn't called the Curse of the Undertaker, it was called the Curse of Naxxramas. Blizzard never made some big deal about Undertaker, and in fact, it sort of slipped under the radar for quite a while before people saw it emerge as the most powerful 1-mana minion in the game.

then a week later

Naxxramas was released on July 22, 2014. The Construct Quarter which contained The Undertaker was released in the 4th week. So around August 19, 2014 is when The Undertaker was released. He was finally nerfed on January 29, 2015. That's over 5 months, not "a week later." It doesn't matter when the OP purchased Naxx, other players had already dealt with the bullshit that is Undertaker for nearly half a year.

without your consent

Odd, I didn't realize multi-billion dollar companies needed the personal consent of every one of their customers to do something.

or even informing you

Here's a post on January 27th regarding the upcoming Undertaker nerf: http://us.battle.net/hearthstone/en/forum/topic/15700587539 and here's the official patch notes on the 29th: http://us.battle.net/hearthstone/en/blog/17796670/hearthstone-patch-notes-2107628-1-29-2015 Oh, and maybe the past 3 months of outrage all over the forums and reddit might have hinted that Undertaker would be getting nerfed.

removed the power windows from your car

Undertaker is still in the game, not removed at all.

and didn't reimburse you

They reimbursed players who had used dust to craft the golden versions of The Undertaker for full value. The non-golden Undertaker was included as part of the Naxxramas package. There's nothing to reimburse for here you dolt.

you'd have reason to gripe

No, as I've clearly laid out here, there's actually zero reason to gripe.

Want an analogy that actually makes sense? So this car company makes this car, it's shiny and new and seems like everything's okay. The car runs REALLY well and is extremely fuel efficient! But there's a problem. The engine works very efficiently, but produces an extremely toxic byproduct. Everyone starts buying the car because of how efficient it is, but this toxic byproduct ends up causing environmental and health damage in the surrounding area. This goes on for months, before finally a federal health and environmental administration steps in, forces the car company to recall all vehicles with this specific type of engine, and alter the engine so that it produces less toxic byproducts. The people get their cars back, they have less efficiency, but it's better for the world overall.

/r/hearthstone Thread