YEEEAAAAH someone used advanced job! lol. Unlimited job sounds about as lame as limited does imo.. /petty reee over here haha. Just sounds great imo, Advanced Job, it's so FF and fitting in concept. Have my silly +1 for spreading the good name XD.
I'd like to argue a little on resource management though. So let's say they went the advanced route, and clearly your argument is to say that would make blue mage costly. Could I suggest the counter to that?
I think at this time making Blue Mage advanced is LESS costly than making a new job, we have so many resources developed for the job even lore, graphics, and basic mechanics. We're half way or more to a job already. Also the limited side doesn't need to be updated at the same rate as the main job side. In this way it's like reusing code when programming rather than reinventing the wheel.
One of the posts I made was a timeline into making Blue Mage an advanced job, so lets say in the timeline where by 5.3-.5 (early better but far less likely) that blue mage has caught up on level and is fully unchained into it's advanced status. Now when they add new spells every other or less frequent patch consider that they're also developing "expansion" content for the job, so this work is even more effective than it would have been if blue mage is just limited. Designing limited content just became an even more effective use of time, and also assures players that blue mage wont become some forgotten mini game too (since they're encouraged to work on it at least occasionally).
I know what you're suggesting with keeping blue mage up and all but IMO I'd strongly suggest that Advanced Job blue mage is the most effective use of resources compared to limited job blue mage, because you're able to create a side content, a main content, and have them strongly marry each other (while separate balance and mechanics out enough that main job blue is fun to play and limited job blue is OP and unbalanced).
So I guess in other words while it's true not doing any work costs less resources than some work that technically (imo) advanced blue mage is a more effective use of resources than many things right now (like upgrading/extending existing infrastructure vs starting from scratch, when you get in a comparison like that advanced blue mage actually becomes very resource friendly).