I must say, the response given in that interview is very disappointing. To summarize, Blue Mage has powerful spells, and to balance it alongside other jobs would necessitate the removal of those spells. At which point it may no longer feel like Blue Mage and for that reason it is to be kept separate.
There are two issues with this response. To answer the question, "Would it even be a Blue Mage without those powerful spells?" Yes, yes it would still be a Blue Mage. What defines a Blue Mage is that it utilizes magic to execute attacks that would otherwise be exclusive to enemies. The strength of those spells is a separate matter entirely and the vast majority of the spells available to Blue Mage in FFXIV aren't even problematic. Take away the few that pose a problem and you would be left with... well, Blue Mage.
The second issue is the idea that those powerful spells would need to be outright removed from the equation in the first place. Those who are happy with a limited Blue Mage with broken spells and those who want a balanced Blue Mage that can be played in all content can both have what they want. My suggestion to SE is for them to utilize a tool that they have already created: Basic Instinct.
Basic Instinct is already a vital spell for Blue Mage to function as a solo job, but its functionality can be expanded. Add the text, "augments certain Blue Mage actions" then allow it to be used within The Masked Carnival and the Blue Mage Log (and if they wish to maintain intended balance, the ordinary passive buffs from Basic Instinct could not apply within those specific instances). A Blue Mage with Basic Instinct active would essentially be identical to the current limited job. You would have your crazy spells at their full strength, but they would only work within the limited content that's been created for Blue Mage and solo efforts. For all other group content, Basic Instinct wouldn't be accessible and without that, we would be left with a "toned down" Blue Mage that's on par with other jobs.
Now this was just my suggestion. There are other approaches that could work too, be that a second job stone, a passive trait, or a stance ability. In any case, don't let anyone try to fool you into thinking that Blue Mage must be one of two extremes: either a limited job with crazy spells or a "normal job" that's balanced. It's entirely possible for both to coexist. Even if you are fine with how Blue Mage is currently, you shouldn't be opposed to a proposal like that when the goal is to retain what you like about it. This is not about taking things away. It's about adding more content for Blue Mage so that more people can enjoy it.