I didn't know such thread existed here on forum. :O
Well, I told my opinion on this topic couple times before in different threads.
Here's what I think.
Littlefoot's motivation differs in different versions of the film (theatrical release and early script version. Different versions of finding the valley): he decided to get rid of Sharptooth to save little group from being stalked by him, or to protect Great Valley from him. At least, this is what movie / script lines try to tell us.
But, at the same time, I personally think that Littlefoot seeked for revenge in his mind. Maybe, just maybe, it was the MAIN reason, his primary desire, and he tried to hide it from others, and even from himself, with making up and explaining other important and valid reasons why they should get rid of Sharptooth.
Littlefoot is a very good hearted boy, yes. Of course we expect to see only good actions and pure thoughts from him. But... he's still a 5-years old kid. With still not fully formed psyche and worldview. Who recently got a serious child trauma.
Let's be honest - remember your early childhood. Remember moments when someone hurted you very badly. It can be serious like somebody hit, humiliated or insulted you, or something silly or moments when you were guilty but you still felt like it was unfair and hurtful. Now tell me - was there cases when your first thought was not to try to reason with person who hurted you, to make a piece with him, to apology, or to ignore and forget him, BUT make a revenge, harmful as possible?...
That's what I prefer to think. No matter what version of movie, behind Littlefoot's pure motives there WAS a revenge. And he used his friends and put them at grave danger when he made them be involved into it, performing a plan to get rid from person who was responsible for great loss in his life.
I prefer to think that in critical moment, right before Cera appeared, when friends couldn't do anything to stop Sharptooth, standing on the cliff, when death was closer than ever, Littlefoot could realize that he put his friends, his huge responsibility (it was his main goal - to lead them to the Great Valley, since the moment when he met Ducky), at grave danger, and he's the one to be blamed. Well, actually, even if there wasn't revenge motive, I think that's what Littlefoot thought at that moment.
Of course such vengeful motives doesn't make Littlefot evil, in my opinion. But it was interesting to see Littlefoot from this side, with dark thoughts visiting him. Thoughts that COULD radically change his personality, form his worldview and and life position, and make him different person in the worst circumstances.
And I think that one of the best things that sequels gave us is introducing Chomper and his parents. There, we could see that Littlefoot didn't become some kind of avenger against all sharpteeth in the world. There, after some new adventures, we could see Littlefoot's formed view of sharpteeth. For him, sharpteeth are regular dinosaurs: they grow up from innocent kids, they have the same feelings, they make families and have their own lives.
After all, like Rooter said: "
lt is nobody's fault. The great circle of life has begun, but, you see, not all of us arrive together at the end."
It wasn't Sharptooth's fault.
After all, Sharptooth himself hadn't any evil intentions when he attacked Littlefoot and his mother. (at least in theatrical version of the film, which I consider as canon, unlike book version). He just acted natural at that moment.
(Seeds of evil could appear in Sharptooth's revenge subplot that was hidden behind main plot - stalking gang for food. In my opinion, this motive also took the place in the story, and it's pretty interesting to see how it reflects Littlefoot's revenge against Sharptooth himself. But that's different topic for discussion.)
Lastly. I just had to...

Good one!
