let us know how the unrooting/replacement goes.
my phone is having the same issue (happened before i rooted). i took it the vzw store and the support guy said it was a common issue, and if it continued to bug me i could have it replaced. i didnt really want to re-do everything on my phone, so i let it slide.
now that im rooted, im thinking about making a backup for the root so i can return it and get a refurb where the keyboard isnt so loose.