Sometimes, I can't help but think that he's an extra character that was added in last minute that the series could live without, but his character is well developed and in situations like
training Hibari and etc, he was rather necessary. I like how he's extremely reliable (as a friend) and he'll come when people need help. The little kick that he can't function without his family
is really funny sometimes but also shows how much he cares about and relies on his family.
I find Dino to be a nice character overall but he seems to be an older, post-Reborn-training version of Tsuna. We know, thanks to the future arc, that future Tsuna is a capable mafia boss so you could say Dino foreshadowed Tsuna's awesomeness to come. Anyway, I liked that he trained Hibari. 8D That was nice to see. And Enzio is one awesome turtle. Dino's a pretty cool character. His random appearances are always welcomed. He's surprisingly kickass sometimes. I wonder, though. Is Tsuna stronger than him yet? I mean, I don't remember seeing him go all out, but the Vongola family is much more prominent than the Cavallone family if I remember correctly, so Tsuna will probably be stronger than him.
I think Amano does a pretty good job giving the mains, like the guardians, their respective fights and whatnot though.. so I won't ask of too much from the sides. I'll just quietly hope for screen time from the cool ones, like Dino.