I think Vegeta going berserk at Trunks's death was better than when Piccolo died, though Piccolo didn't really die, he was just on the verge of death like Trunks.
Piccolo was just...unnecessary, unlike Krillin who pushed Goku to his Super Saiyan status. Piccolo didn't affect much. But like Sirlian said Vegeta realized and accepted he was a father.
I do think Gohan should have been built up more, Toriyama had a good idea with Goku and Gohan bonding before the final battles but he could have done more. A shame because he wanted Gohan to become the true successor to Goku. Cell Saga was great though, no true problems beyond that. I think the Frieza saga could kind of drag though, now that I think about it...I love the Buu saga, it has issues but it really is good. My chief problem is that while I like the idea of Goku and Vegeta teaming up, having Gohan, Piccolo, Trunks and MAYBE Goten, because I don't care about Goten at all, would have been awesome. They've been among the main fighters, Trunks in the last season anyway, so it would have been cool. The reason for them dying was stupid too, why didn't Vegeta save his own son after his rage at failing to do this in the Cell games? He berated Goku for not doing the same. Not to mention I was really hoping to see Gohan and Goku team up against Super Buu but then Gohan got absorbed and didn't do much. I really wish Adult Gohan did more, he was MIA for a great deal of the Buu saga and he had some great moments fighting.
As for Goten, I don't like him at all. Future Trunks was a lone warrior who saw a lot of traumatic things and was humble, while Kid Trunks was like how Vegeta would be as a kid but far more child-ish. Goten was just a whiney and stupid brat. I think he was only put in for an equal to Trunks or just for Gotenks. Also it was a shame that Vegeta became outclassed by Goku so hard toward the end, and that we never got a true, finished battle between Goku and Vegeta. Buu is a good villian, but his 'can always regenerate from everything' is broken, and got old so quick. I think Toriyama had some pressure though since he was forced to abandon his idea of Gohan being Goku's successor. Beyond that I think all the sagas are great, but have their own separate problems. Also...
Does anyone find it weird that Goku was surprisingly ok about Gohan's assumed death?