At the moment I can't particularly imagine anything that could lead to a new rupture of the crew. Sanji is on his way to finding the all blue, zoro so far seems on his way to being the strongest swordsman and luffy so far is not an obstacle, robin could not have a better shot at the true history with another crew, the sunny does not seem to be improperly taken care of so franky is fine, nami has not had any trouble making her map, ussop has the best shot at becoming a warrior of the sea by continuing his journey with everyone and there is no reason for chopper's dream to be stopped by the crew so far... Dreamwise at least, there is no reason for any strawhat to quit so far and for the most part that is the only reason a crewmember could have in order to consider such a thing.
Now, a little less realistic but still worth considering is the crew seeing a deficiency in luffy's leadership. be is strength-wise or simply because luffy's recklessness finally got them in more trouble than what they could handle it is something that could eventually happen and from which luffy would have to learn. This would be an issue with zoro in particular who is somewhat less forgiving than the rest of the crewmembers. He was the one voice of reason when it came to robin's betrayal during the water 7 arc and was certainly the coldest one when it came to ussop's fit after all. His loyalty to luffy is unquestionable however I have no doubt that if he in particular were to see a deficiency in any particular crewmember (including luffy) he would act no different than from when ussop had a fight with luffy and be as adamant in his position as he was before (and otherwise make a ruckus and leave as he said he would do if ussop was admitted back without a proper apology).