I think it is more likely that we're Tempered. Tempered individuals, given time, do seem to exceed their mortal limits to the point where we have to deal with them rather than them just still being random pathetic people. This is particularly noticeable with Ifrit, when we get to see him Temper some people, who then meekly walk off to their deaths, yet all the other Tempered individuals for Ifrit (presumably coming from similar walks of life) are fairly strong (or were, at Lv50). How'd they get that strong? Simple, being Tempered makes you stronger.

Who are we Tempered by? Hydaelyn, of course. Both the planet and the Mother Crystal. The Mother Crystal is actually in the center of the planet, looks awfully similar to Bahamuts crystal heart, doesn't it? But Primals sap the world of aether to sustain themselves? Well, Hydaelyn is a planet size Primal, does space look particularly rich in aether? The Lifestream? Well, would a large enough Primal have a vascular system? I'd think so...

Another interesting tidbit from the Alexander plot line, the Illuminati seem to think that, once Alexander is fully operational and consuming all the aether on the planet, they'll be safe inside, surviving off his aether. So, unless they're wrong, large enough Primals can sustain life inside/on them. Wonder what would happen if you summoned a Primal inside Alexander... Would it feed of the planets aether, or would it feed off Alexanders? Then there is the whole Ascian thing. Most recently they've claimed we mindlessly seek out Primals to kill, and in the past Elidibus mentioned how we'd join them if we knew the truth... From their perspective, we live to kill Primals, but we're unaware Hydaelyn is a Primal. If we knew Hydaelyn was a Primal, surely we'd join them to kill yet another Primal?