As far as the first question, I really like Doc myself. I'm naturally drawn to your quiet loners who have more to them than they let on. I'd really have liked to hear Doc talk about where he's been and what he's seen from his perspective, as a point of opposition to the tall tales surrounding him. It wouldn't entirely tie in to the ideas of the movie, ie, that whether they're wholly true or not, stories are part of how we figure out who we are and how to approach the world and how to relate to others. Still, I'd have enjoyed the addition.
I don't really have much to say about his TV show appearance, though, it's always interested me that he points out that Chomper is likely to become at least something of a threat to his friends. Whether he's "mean" or not, he's a flesh-eater and he will need a lot more substantial nutrition as he gets bigger. It's not really explored much, but interesting nonetheless. Honestly, that could make for a whole story of its own, with Chomper and the gang coming to terms with the realities of the world with Doc's input and experience. Probably would need more than that, but general idea seems neat to me. Also kind of interesting that Doc was introduced the very movie after Chomper made his second appearance, and the gang even managed to get along with his parents alright there. "It's a good thing sharpteeth aren't very smart" is kind of an odd shift after we learn that they have families and can talk among each other just like leafeaters.
Also, maybe it's just me, but I'd die of happiness at a LBT character in the same loner-who-can-fight as Doc, but either a therizinosaurus or a deinocheirus. Maybe less wild west hero and more sword-master archetype, but someone with a similar attitude who's seen a lot of fights in his or her time. I like the diplodocus angle, I really do, but I can't help but imagine. Especially since I've been so disappointed with therizinosaur characters like the Yellow Bellies and Wild Arms. That's kind of another thing about Doc. Most of the new characters introduced in later movies are largely cute or comic relief, Mo, the tinysauruses as a whole, Guido. Not to say there's anything wrong with those characters, but I always liked how stoic Doc was among introduced characters. He's not exactly friendly, but he's not a threat either. He's clearly a good guy, but he's old and quiet and doesn't open up easily. It's a nice bit of variety.