The issue is not "They should make this like FF XI to the point where the jobs are so indistinguishable from one another that they form tiers within themselves", the issue is that they basically seem to have no desire to even try anything out of the ordinary before even seeing the results.
The issue is that they are basically admitting they won't even try to make the classes different because they've trapped themselves within the confines of the way abilities are learned in this game, as well as how many you get and how they should be used.
It's one thing to say "We want to strive towards this ideal of all the classes executing their role in a similar fashion, but we will work on allowing for some greater variety and balance accordingly if problems arise" and another to say "We aren't even going to try to implement this job because it doesn't conform to the pattern set by the other jobs in the game". Which is exactly what their stance fundamentally is about Blue Mage, regardless of whether or not it would actually be effective because it doesn't fit the three molds they've based the game around they won't even consider it.
For me the irritating factor is that they won't even consider jobs of varying complexity (Such as more advanced pet mechanics on SMN or a non-standard amount or abilities/non-standard ability procurement for something like BST or BLU) because of the notion that everything needs to be for everyone. I don't see anything wrong with letting people who enjoy more challenging mechanics enjoy them, if people can't cope with them they can either learn to or find alternatives.
