I like Saro, but I don't like him in the episode he appears in... I'm aware that statement makes no sense.
As I do with obscure characters, especially any of those associated with Littlefoot's family, I made many a headcanon for Saro. I guess the way I write Saro in fanfics made him completely different to how he was in canon and that's the version I liked.

But I'll talk about his canon appearance before I ramble on about my fan speculation.
Saro's a manbaby.

There's something I said about the episode "The Legend of the Story Speakers" years ago which I still stand by today: Saro's reaction to Grandpa saying 'no' to coming back to story speaking was extreme, and if he always sulked like that when something didn't go his way, I can't see his and Grandpa's friendship being as strong as it appeared at the start of the episode. I can understand the disappointment, but to just sulk off back into the Mysterious Beyond with a 'I have nothing left to say to you' after supposedly searching for his friend for years... kinda petty.
Short speculation time:

I imagine Grandpa and Saro met as young adults and travelled together as Grandpa told the stories and Saro listened. Saro may have looked up to Grandpa as a big brother of sorts, being taught and guided by him as he learnt the stories. I wonder if Saro is maybe a bit insecure, not feeling confident that he'll be able to do the job as well as Grandpa (who he says was one of the finest ever), and that's why he wanted Grandpa to be the story speaker again instead of him.
Saro had a lot of potential and I liked that we got a glimpse into Grandpa's past through him, but he wasn't written that well I think. I'd like to see more of him, although I guess that's unlikely.