The Dragon isn't hanging around to pick up in the Adventurers Inn like other early-game characters. He's out in the wild, and you have to find him, and unless you've already planned out where to go, it will be a while before you pick him up anyway. By that time, he's still useful, but far from game breaking, and you may well have developed other characters beyond him. His biggest bonus is flying as far as I'm concerned, not overall fighting power, and if you apply the same method to your Necro as you have to with the Dragon to get flying asap, your Necro might well get Master Air Magic before you find the Dragon anyway.
Interestingly, the Dragon's weakest element is Endurance, so he's a bit of a glass cannon anyway: lots of strong attacks that will wipe out groups of low-level enemies, but at higher levels he's often the first to drop and no stronger than other might classes