Yes, Don Bluth himself considered him as not evil.
Only thing he did that went outside borders of nature - is trying to kill Littlefoot not only of hunger but also of revenge. This action moves my favorite sharptooth right to the border between being just natural predator and creature with evil intentions, but he definitelly didn't cross this border.
His first and third encounters with gang was pure fortune, I believe he didn't intentionally stalk ONLY gang. Due to hunger and terrible fight with Littlefoot's mom and fall to the abyss, he tried to eat small prey like children.
Third encounter (awakining) was also fortune plus Cera's actions, and btw, I do think he didn't even realized Cera was here, he just woke up from terrible fall and microcoma, so he possibly could not recognize nearest objects.
Final encounter could not even happen, he could juss pass through...
If Littlefoot didn't want to make evil revenge and risk his and his friends' lives only to make a vile deed and kill innocent creature who only tried to survive hahahahaha Littlefoot is the true villain! 
*calms down*
Ok, final encounter could not even happen, if Littlefoot wasn't afraid that Sharptooth would find a valley and tried to get rid from him to protect his new home. BUUUUT I still also thinks our lovely longneck thought about pure revenge, and if not Cera, his revenge would cost lives of him and his newfound friends, that's not good.
I think Littlefoot also went veeeery close to border between being just natural dinosaur and creature with evil intentions... In the nature, herbivore creature doesn't just kill passing by carnivore, right? He does it only if there's direct danger to his life or his family.
Sigh... Revenge births another revenge... Evil births another evil...