That does bring up an interesting point...possibly another addition to the messages about the difference between species, etc. Though yes, the predatory nature of the sharptooth would have been mostly under-minded by the fact that he/she? would have had a youngling to look after. Depending on how the story went, the children could have maybe even befriended the sharptooth in the end by saving/helping the sharptooth's brood, like in V, hehe.
I think it would have been interesting, and probably less dramatic in the end. Then the whole struggle with the sharptooth would have been more overcoming of differences rather than a blatant fight of survival. But, like I said, it would have all depended on how the whole situation was presented. As interesting as it sounds on paper, I think the actual practice would have made the movie even more moral-intensive and possibly driven even more towards a child audience and most likely would've made the movie less tense and scary- BUT- Don Bluth has tendencies to take his movies in dark directions despite the fact that the whole animation aspect turned them towards children and such. The Secret of NIMH proved that to me, as, when I really think about it after reading the novel and watching the movie, that Bluth can take young-adult themes and make them understandable to those who aren't necessarily young-adults with just the animation and the situations of the animation.
Then again, I'm on pain medication right now so I'm probably just rambling.

Silly wisdom teeth.