Snares aren't Roots.

While rooted, you'll only DPS those in melee with you.
Still you have some healing, and a bit of ranged DPS.
Mages are annoying, they won't necessarily kill you.. but they'll prevent you from killing others too.

If you're doing BG's, I'd think about the Fire Elemental glyph, for 5 minute Fire Elementals.
Haven't really done much Enhancement play.
But it's worth a shot.

Rogues are also annoying.. sap one member of your team.
And then switch to another member and sap..
Buggers.

Still you have Tremors on round-robin.
Which negates Fear, the other thing that sucks for boxers to deal with.
That is a huge boost in favor of Shammies vs almost anything else.