What would be interesting is for Littlefoot to actually spend a season with his father; to just give migratory life a try, with the promise that he would return to the great valley when the season was over... On the migratory path, he would probably see amazing stuff, blah blah blah, cue song sequence with montage, etc... but he would also be exposed to some uncomfortable realities of living in a migratory herd of sufficient size. Now, when he was young, Littlefoot WAS migrating to the great valley, but he wasn't so much with a herd as he was with his family... Bron's herd would be different. One can see an interesting story involving herd politics and the measures Bron has to take to lead and control the herd. What would be interesting as well would be if Bron had to fight another sauropod for leadership of the herd, and then have to explain to Littlefoot about exactly why he had to fight to maintain his leadership... something along these lines:
(Fight between Bron and rival ends in victory for Bron after fight sequence)
Bron: (some blood is visible going down his mouth where he was hit) *Pant, pant* (catches his breath after the battle)
Littlefoot: Dad! What happened! Was there a sharptooth attack! Why is that other longneck lying on the ground?! (stunned, not badly hurt and definitely not dead.)
Bron: I fought him, Littlefoot. He was... trying to... take something... Littlefoot. Something that I have and that I will one day give to you...
Littlefoot: (confused)... What could you possibly have that he would want? Were you fighting him over some food?
Bron:...(pause)... Littlefoot? Do you know why I am the leader of my herd?
Littlefoot: Is it because you can see things they can't? (shadows of Pterano)
Bron: ...No. I'm not smarter than most longnecks, and I'm not chosen by anyone to lead...
Littlefoot: So, what are you saying?
Bron: I sort of... became leader of my herd because I was simply able to protect everyone. I was the biggest, and the strongest... and as I have just proven to this member of my herd, I am still the strongest.
Littlefoot: ... But... don't they... love you... as their...? (Littlefoot mistakenly thought that others in the herd treated Bron like Littlefoot treats Bron)
Bron: I am respected by all, loved by some (more on this later), and feared by a couple of others... they need me as their leader, Littlefoot, but not all of them like me all of the time... some of them think that they can do things better than I can... Some of them want to prove it by force... I can't let that happen...
Littlefoot: But... what about... talking out your problems? In the Great Valley, the grown-ups meet in a circle to discuss things.
Bron: I know that, Littlefoot, but the Great Valley isn't here. Out here, people are less patient, and far hungrier... they don't want to talk or listen... and I have to do what I need to in order to stay a leader...
Littlefoot: I don't think I like that very much...
Bron: It's what we do out here...
Another scene could be too tricky/controversial to put into a children's movie. In the wild, Bron might be considered an alpha male. In some animal groupings today, the alpha males are the only ones who mate, or at the very least, get the "first pick" of females. While it is unknown whether such behavior was present in any dinosaurs, it is not unreasonable to assume this could happen. Now, showing something like polygamy is not exactly... kosher... to show in an American animated movie, but we might see the side-effects of it. Tippy's herd, for instance, shows him with his mother but no father. Since the stegosauruses lived in herds, it isn't unthinkable that the alpha male who led it (Tippy's herd was led by a male, after all), might be the father of at least some of the children in the herd (or child, as we only see Tippy.)
Showing Bron in that capacity would be rather tricky... but it would be both relevant to nature and definitely interesting... to see how it would be handled.