The 3 supernova all took the worst road possible for each other. Had Law and Kidd go to Egghead they would have just lead, no fuck given about Bonney and Vegapunk.
If Luffy went Law's way he would have face BB with only 3 officers, straw hats would have won.
If he went to Elbaf, friendly encounter with Shanks
As for Kidd, his personal grudge vs Shanks makes it the hardest road
And Luffy is facing a fleet of 100 ships with 1 admiral, 1 gorosei and 4 seraphims