Swipe being directional doesn't mean a thing when you're talking about balance between tanks. Hell, with creative strategizing (read: holy pally with righteous fury?) you can easily pull any number of adds into swipes are of affect.
The thing that's so unbalancing, and what's really boggling me, is how MUCH threat swipe is. If you can hit everything, you WILL get it all. And that's in it's current iteration. I don't see how they can try to improve it when it's already so powerful when used properly.
The only real solution that would make druids more in line with other tanks would be to make it easier to use (wider angle, larger range, w/e) and nerf it's overall threat, via cooldown, or reduced threat/damage modifier.
At some point, these abilities are going to have to be homogonized to some degree. There's no viable reason to make an ability stronger but more difficult to use. I mean, how many different ways can you "hit all the mobs around you"?
"He who fights with monsters should look to it that he himself does not become a monster." -Frederick Nietszche