Here is their track record for patches and content from start to now.
Up until late ICC they had an incredible amount of content released. Even the latter half of ICC wasn't bad because of the real id and dungeon finder stuff. Ruby Sanctum was something. 12 months of ICC was understandable with all the work they did on the world in Cata.
Cata was fantastic until 4.3 for the most part. Sure it was a slight reduction in patch quality, and a significant reduction in quantity (raid wise), but it still was good, and I think the world revamp took a lot from the end game. Heck, Cata is the only expansion that really had a lack of raid bosses. Maybe you could argue WoD, but with only 2 tiers it still managed to have more bosses. Raiding isn't everything though. When an expansion releases they usually have the first major patch heavily in development. Stuff happened and we got Cata. We thought it was terrible, but it wasn't that bad.
MoP was a return to form imo. Lots of quality content, and a ton of it to boot. The only negatives past the first couple months of required dailys was the lack of new dungeons and the last 6 months of SoO. Even until mid 2014 Blizzard was doing well.
WoD is an outlier. Something happened between the time they launched 5.4 and 6.0/1/2 that made WoD terrible. Who knows what that was. We may never know, but only 1 expansion out of all of them plus the base game was truly terrible. The rest were good. Why not give them the benefit of the doubt one more time for Legion? I know I am.
What are your thoughts on the matter? Do you agree with me that the other expansions were good and only WoD is a true misstep, or am I wrong? Also, what do you think happened with WoD? Its obvious something happened after 5.4 that ruined WoD. I truly believe that it was meant to be a 3 tier expansion with lots of cool stuff, but they had to scrap so much that it ruined it. I think that WoD was never meant to be a 2 tier expansion, but it was easier to claim that when they realized they couldn't deliver than to tell us what really happened. Im betting Legion will be 3 tiers.