I wouldn't like the aura as much as a trail... the fact that you'd actually have a lil bit more luck finding your opponent, when swooping around each other at close range..
Even though i think i am allowed to say i am not a bad player, i often find myself pausing battle for a second, to find out where the hell my opponent exactly winded up, seeing my opponent do exactly the same..
Since radar doesn't show height, and while swooping (close range) you don't always have the oppertunity to check the thing in the first place, so you'd find your opponent much faster if he left a trail..
Wouldn't have to be anything fancy, just a short ( ? ) decent looking trail.. servers wouldn't suffer that much this way either.. (i think)