I just want them to let Goku go already. Yes, he's the main character, but that doesn't matter. If they intend to make Dragon Ball a long-running series that goes on for decades without an end, either reboot it or get a new protagonist before it becomes the new Pokémon, with a never-aging protagonist who doesn't change or learn from his mistakes.
I don't feel they should give Goku the boot entirely. His role just needs to change. With Uub, we can meet Goku the teacher! Meanwhile, Uub can have a co-star role. The interaction between the two has potential. For example, I don't see Uub being like he is in GT, where he's sparring with Goku, just goes along with it, and becomes a generic Z-warrior. For the start of the series (or 2nd season if it's pre-EoZ at first), I'd personally love to see him as a bit incompetent as far as fighting goes, despite his ridiculous inner strength. Like, despite Goku taking him in after realizing he can't fly, Uub still hasn't learned to fly! That in itself can be a running joke for a while if he finds himself alone with 4 year old Pan, who can run circles around the world. The way I envision Uub is sort of like Tenchi from Tenchi Muyo; awkward and unassuming. On the other hand, Goku has this tremendous confidence in the boy's abilities, so he puts him in ridiculous "training" situations that result in the lulz.
I'd just love a mini-"Uub arc", akin to the Great Saiyaman one, before moving onto a major saga. It'd allow us to become familiar with the character enough to want him on-screen later on, and in a sense, he can act like the audience's lens into the DBZ world since he doesn't really know any of the cast, has lived in a remote area all his life, and is just starting his new life thanks to Goku, which involves school, family obligations, and training with Sensei Goku-san. Goten and Trunks can be his seniors in school. Gohan, a teacher. I'd love this so much.