I know it seems late for Usopp, but I'd rather him look like a bum and attempt to develop him into someone heading on the right path of growth. Perhaps armament haki developing stronger bullets (kinda like how Yasopp can blow a ship up with his). He just looks like a bum here and while it's late, better late than never.
I used to really like Usopp, this doesn't need to be his arc, but he gets a lot of panels most arcs, would be nice to see some greatness from him, even if only a few key moments and the rest just him heading in the right direction for the rest of the manga.
Nami's fine. She tried and she has a strong power. Yeah, it's weird that Zeus couldn't defeat the cat, but at least Nami wasn't helpless.