Usopp f'n sucks. I don't understand why Oda would even create him as a character. He's made no progress at all in becoming a brave warrior of the sea and he's still weaker than fodder. We're almost in the endgame.
He's a pointless character. Just like many of Oda's pointless side characters. He doesn't need any more screen time other than a few panels for the rest of the manga, its too late to try and make him important in the grand scheme of things.