The levelling process is not fun for new players.
The teaching it should be offering is killed by the community and the "Go, Go, Go!" attitude where everything has to be as fast as possible.
Is it then any wonder that blizzard are offering a way to skip much of that.
It has been said there will be at the start of WoD an "introduction" to the fundamentals of any given class boosted to 90 (not sure about those boosted prior), which if executed well could teach players more than the 1 to 90 is currently providing for many.
If the players were more understanding that some want to actually learn then the experience might have been vastly different, and the boost might not have been necessary.
I would argue most of the "convenience" features that are most complained about are necessary due to the behaviour of some players, of which those doing the most whining are often a part of.
The community creates most of the issues it complains most loudly about.