In all honesty I still don't think GT or Super should exist. The story was over for Goku, Vegeta and the rest of the OG Dragon Ball cast. A lot of stuff was resolved outside of Goku abandoning his family for Uub briefly but even that wasn't too bad. However, for Gohan, Trunks (both versions, maybe) and Goten, having a series that primarily focused on them would be fine because it'd be interesting to see how they develop. Heck we only had the Buu Saga for Goten and Kid Trunks, and Adult Gohan could be interesting to see how he manages as a father, warrior and scholar. And I do agree about the devolution, especially for Goku. Vegeta still has a natural need to be better than Goku and everyone else, so he's all right there but I feel everyone else devolved too.
On the dubs, I think that may be the case because some dialogues and changes are made between Japan and America, which isn't unheard of with other animes. I did get a maturer vibe from Goku in the Z half of the manga versus the DB part, to be expected but the American anime totally cranked it up