An interesting topic for sure...

Something similar I've been wondering myself since day 0. Not so much one job being almost a carbon copy of the other, but rather the customisation (...lack thereof) of the individual jobs. Summoner 1 is always going to go through the same rotations as Summoner 2. WHM 1 will always try to conserve mana and be careful about Medica II just as WHM 2. MNK 1 will always going through the same combos in the same order as MNK 2. And so on. Get the picture? Some minor differences, maybe, but that can (and will) be usually chalked up to a botched rotation - lack of skill ("you're such a noob!") or a mistakenly pressed button. From what I can remember, in 1.0 CON sure could have a little custom flavour to it with the elemental adjustments at least. It was nice, imo.

As for crafters...they are useless. Save for 50+ gear (also crafter/gatherer, because dungeon loot is unquestionably better for DoW/DoM), which then is the flipside of the coin, requiring ridiculous materia overmelds for each and every piece, which in turn requires ridiculous amount of investment to get there. And some glamour gear and furniture which again require ridiculously overmelded gear to craft. Kinda meh. :/