Does agility help focus?

So, Misty and I completed her beginner obedience class this Monday. She only has one problem--and that's to focus around other dogs. She would focus very well the second half of the class, but most of the time, before that, she would busy herself with watching the other dogs and trying to convince me to let her play. Here's the kicker. She would sit, down, etc, when told when staring at another dog. She WOULD NOT look at me, but she'd obey my commands. She stayed marvelously and came without veering off to another dog. I could drop the leash, walk across the room/outside area, and she'd stay until released and the come to me. She waited excellently at all doors.

I don't get it. She'll obey just about everything.. It's just trying to get her FOCUS that became a chore.

We did an exercise in which we each lined up and one at a time weaved our dogs in and out of each other's. She constantly tried to get at the other dogs, no matter how much correction/encouragement/praise for walking correctly she got. Whenever a dog would walk past, nothing I could do (treats, toys, acting like a playful madwoman) could get her attention. Only for one dog going past did she focus on me. I suppose that's progress..

Anyway, with obedience over, I'm wondering what I could do in the near future to encourage her to focus on me. I've always wanted do agility, so I asked the trainer if she thought Misty was a good candidate. She said absolutely, saying that Misty DOES focus on me, she just does so with her peripheral vision. I'd just have to wait a few more months and have her examined by a vet.

Now, onto my question after my rambling tale.. ;p

In your experience/opinion, does agility help improve a dog's focus?