can't happen, if you scale the other jobs up to be in the same league as the current "flavor of the month" jobs, the people on the "flavor" jobs will whine about how weak THEY are, it's a never-ending cycle. Example:at 75 red mage was the end-all-be-all of healers and whm was only there to raise, if at all. So, they made white mage useful again and now the only way to find a rdm who isn't bitching about it is if you chop off their hands and tongue before you ask their opinion. I'm not saying that rdm doesn't need to be scaled up, but odds are doing so will marginalize white, black, scholar, bard or corsair depending which direction they decide to scale it.
It's not the developers problem, it's the playerbase; we find 1 way that works to beat any new content and stop looking for more, sending any job that doesn't fit the build for the strategy to the trash heap. Again, to use red mage as an example they've announced that enfeebling magic is going to start working at end-game levels; since red mage has the best chance of landing an enfeeble and there is no appreciable loss of XP on death it's entirely possible that white mages days in end-game are numberred once the enfeebling is worked in to "the only way" to do (fill in the blank). So how is this a "playerbase" problem? Well, white, black, blue, summoner, bard, nin, cor, sch, and to some extent pld and dark are all capable of enfeebling a target (the enfeebs vary), but the playerbase will simply ignore that and call the jobs "gimp" since red will be the accepted enfeebler.
This goes for any adjustment they make/content they add. Seriously, give it about 3 weeks for the posted strategies to get out there after the update where this happens, then watch the forums here, you'll see.