Haha thanks, love the term "grunty." And that's pretty much what they would be. They would be Eorzea's gift to each adventurer as a means of physical support. Eorzea's middle-man/helper/sidekick all in one. No other creature in FF-lore could fit this role but the Moogle.
Here are some other examples of games with "grunties" that are doing it right. My hope is for FFXIV to expand greatly on the concept:
PSO Series
http://phantasystar.wikia.com/wiki/Mag
I like the PSO series' way of using companions in battle, allowing for burst abilities/special moves, support, and for Mag customization via feeding it items towards a branched evolution path (not that I'm proposing feeding Moogles). FFXIV could take this one step further by allowing us to customize our Moogle in various ways so that each of us could run around appreciating each other's Moogle builds; as well as giving us the freedom to change our Moogles' jobs as we see fit (which would involve training and leveling their jobs up of course).
(latest image from PSO2 mag concept)
Monster Hunter Series
http://monsterhunter.wikia.com/wiki/Felyne
This comes pretty close to the feel when it comes to battle participation, literally having a cat-like companion providing field support. FFXIV would take this many steps further by allowing Moogles to not only throw you battle support or potions, but also providing magic support and buffs (Protect/Shell) depending on the build you've trained them into.
Pokemon Series
http://en.wikipedia.org/wiki/Pok%C3%A9mon
Allow me to explain myself before thinking I want FFXIV to turn into Pokemon. The most obvious link I'm making is the Pokemon's concept of raising various companions and pulling them out in battle to fit the situation. FFXIV could utilize the concept not by raising multiple Moogles, but by leveling one Moogle's various jobs up the same way we level our own avatar's. Once our Moogles are specialized in specific ways, we would use them in battle combinations that best fit the situation.
Best of all, SE could implement a Moogle Battle Coliseum where we could pit our Moogles against each other. Moogle PVP anyone?
Anyway, if anybody can think of any other comparisons to support the concept, I'd love to see them!