A 1" bullfrog isn't a freak of nature, and though on the small side it is still normal. See the chart of metamorph sizes here: Untitled Document and they found new metamorphs ranged from 2.5cm to 5.2cm (1" to 2") with an average length of 3.7cm (~1.5"). It's probably worth pointing out that most of the time the resulting metamorphs end up considerably smaller than the tadpoles they were only a few short weeks ago.
Unfortunately the same website doesn't have info on leopard frogs, but they do have stats on the very similar pickerels: Untitled Document and they are even smaller than bullfrog metamorphs. This agrees with my own anecdotal pond observations of the many leopards I have nearby. So I wouldn't consider the size of a 1" leopard frog to be an impediment to it's survival.