I guess he has the perk of having the most successful manga of all time to be granted the ability to write how he wants the story to progress.
He has a very good world structure and things pay off years later. Most mangas are written very short sided.
Most artists don't have the ability to do how they envision. The publishing house has a lot of say about the general plot.
I remember a toriyama interview, in which he stated that he wrote from chapter to chapter and his editor had a lot of swaying power. This was the reason why we had basically three villains during the cell arc.