All the Straw Hats dreams are linked as they share this Journey together. Luffy brought them together in his quest to become Pirate King, and in that quest, they will all achieve their dreams.
The reason why the Straw Hats glorify Luffy's dream is because they know the closer he gets to achieving his dream, the closer they get to achieving theirs.
This was established in the very beginning of the story with Zoro placing his dream in Luffy's hands by saying if Luffy does anything to compromise his dream, he has to commit seppuku. This was essentially Zoro saying, by following you, I'm am trusting I am following the right person on the path to achieve my dream.
This is not Oda "overdoing it", but rather sticking to a formula he established at the beginning of the series. It would just be weird and make the Straw Hats feel disconnected as a crew if they all run around proclaiming their individual dreams all the time when the fact remains that all their dreams are all linked to a common goal.