@Mr.:
Not if Zoro fight and beats Mihawk first.
Or the Rio Ponyglyph/True History isn't on Raftel (same with One Piece/All Blue/Panacea). This could potentially apply to unknown future recruits as well.
For that matter, would it logically make sense that Nami is the LAST to complete her dream? She hasn't been to the other three Blues (to our knowledge - it's possible she was born in one of the three Blues or traveled there while part of the Arlong pirates) but right now they're just on the Grand Line - that girl's got a lot more to do if she wants to a map of the ENTIRE world.
I guess that would go with Franky, too - isn't his dream to sail all over the world, not JUST the Grandline?
In my mind, Usopp has, to a certain degree, already reached his goal. I think it's a proverb or something someone once told me, but bravery isn't necessarily the act of not being afraid of something - sometimes being brave is doing something even when you're TERRIFIED to do it.
Usopp is a chicken - he's afraid of a lot of things, and some of them understandably so. Good example? Enel. He watched Enel fry Sanji - arguably the third strongest Straw Hat in the same league as Luffy and Zoro (and even if you don't agree with that it's still probably that Sanji is a lot stronger than Usopp against most opponents), BUT STILL TRIED TO PROTECT NAMI ANYWAYS. His knees were shaking, he could have easily wet himself, but Usopp had to gather up every ounce of strength he had to go up against Enel like that.