I would like to chime in, and both agree and disagree at the same time. Playing a game for a certain number of hours might make it worth the money spent on it, but spending a lot of time in a game shows a deeper investment. When a design decision that you don’t agree with is made, it would be easier to dismiss it if the game only had its monetary value for you. However, if you disagree with a change and it’s a game that you’ve sunk a lot of hours into then it can feel like worlds colliding.
Either way a complaint is feedback and it all counts. As long as people are addressing the issue and not the individuals surrounding it (i.e. players or developers) then we are happy to read it and pass it along.
I think what Blizzard needed to take away from the feedback that they got is the sentiment. If someone buys a video game for $70, they will play it even if it is absolute garbage, simply because they don't want to feel like they wasted their money. In Diablo 3's case, they will play it a significant number of hours because they will want to see if it gets any better. Moreover, you cannot trade the game back in because of the way it's tied to your Blizzard account (I know that I would have traded in my copy of D3 if I could, even for only $1 because it is completely worthless to me now.)
The important thing in this case isn't the hours spent playing, but the amount of entertainment that was had during those hours. And with D3, there was very little. The hours were spent trying to get to the good stuff, which turned out not to exist.
Compare that with a F2P game like League of Legends. There is no feeling of obligation that you have to play to make up the money you spent on the game. If you play for 15 minutes and it isn't fun, you can stop and you're happy that you're not playing anymore. If you've played for 150 hours, you played because you enjoyed the experience, not because you were trying to make the game "worth it".
So yes, D3 was a good game because it sold 7 million copies and generated $500 million in revenue for Blizzard. It was a bad game because I won't be buying any more Blizzard games after this because I don't appreciate being tied to a game I don't enjoy playing. The $70 Blizzard made off of my copy of D3 is much less than they would have made from me if D3 was actually good and I renewed my WoW sub, bought HotS and the future D3 and SC2 expansions.