Ahahaha I love the idea of getting high enough rank in your GC in order to lug around some Recruits or Privates. I wouldn't even care if they were level five, all the time, with no chance for growth. Blow your whistle, out pops a Storm Private Second Class (or a whole team of them!) (with an appropriate /gcsalute to their superior), and you order him (or them) to charge headlong into Treasure Hunt mobs or Beastmen Dailies.

Anywho, I like where this is going, OP, but since FFXIV is leaning more toward a traditional Final Fantasy, I don't see us getting more than our Company Chocobo.

Although, the dev. team could take a page out of the FFXI dev team's book, which apparently has a similar companion system to what you're asking. (Disclaimer: I've been away from FFXI for two years and I'm only going by what I see on the forums.)