I highly doubt it will be any more "kiddie" than the series. With the series, they have a shot at expanding on the universe, which, we all know, is an opportunity the makers are not going to take, yet again, despite being handed the opportune moment to do so...yet again.
I like the idea of having a reoccurring villain and having a villain's motives being "revenge".
Perhaps they should get a new villain (one that actually matches the original sharptooth in being menacing), and have him be beaten once, and then have him return to get the kids back for owning him on their previous encounter.
Then have him show up, from time to time, but not so often that his menace goes down.
Also, perhaps, have him merely be the "plotter" of a lot of their troubles, sending others to do his dirty work for him. This would potentially lead to the dynamic of the heroes not knowing that it is actually 'him' who is the most current threat all the time, as well. They know it's him sometimes, of course, but they don't always know it's him. This might also lead to some episodes where Littlefoot and the others think they're doing right, but are actually playing right into his claws, and only realize this when it's almost to late.
Also, what if the Great Valley dinosaurs merely "survive" some of his attempts to get them, without him actually being beaten all the time, physically or intelligentually. What he was the actual winner from time to time, but not winning in a "killing one of the main characters" way, of course.
This character could, say, be an intelligent sharptooth (T-Rex).
This way, they would have a consistant villain, and not have him be uninteresting or unscary if they deal with the character right. Trust me, this series seriously needs a good, serious villain again. It would not hurt anything if the series had a cold, calculating baddie.