Also gonna need to see Usopp either to repair his relationship with Luffy or go his own way and goto Elbaf. And then we're in store for a Koby/Helmeppo, with a badass looking, scarred up Usopp (which every Usopp fan would love!). I think if we get Franky, we could use abreak from Usopp anyways. Need to get used to one comic relief, before we get into another one.
I have to say, as much as I love Usopp, that having him follow the Giants to Elbaf and actually getting stronger would be…. interesting. Especially as I think it's likely Elbaf is in the second half of the GL (this is just speculation, seeing as how strong the Giants are) it would mean that we would likely not see Usopp for a good long while to come.
Although I think it's far more likely Usopp and Luffy will make up, the fact that, in-the-end, Usopp was unable to face him and still kept the mask of "Sogeking" may be an indication of a departure. Who knows... Oda does!