Do you think he came up with the succession war plot during the hiatus before the DC arc started or was this something he had planned for a while?
I can tell he started writing the CA arc when he really got into Parasyte because it follows a lot of the same thematic elements, I wonder what was the hiatus inspiration for this arc.
I don't know the guy, but I visualize him as the type who writes all his plans on sticky notes, loses some sticky notes, rewrites some with slight differences, loses more, rewrites more, swaps order by accident and so on. Basically, I think he has come up with the plot many times based on the based on the personality we see in the author's notes and narration. Whereas we have seen Oda's over-the-top organization with all the notebooks. I definitely think he has been planning a Kurapika focused arc ever since he got more into the more cerebral CA characters like Morel, Killua provides some of that, but he still tends to handle things through violence. Also look at how many missing pieces were left of Pika's goal the last time we saw them, he definitely had some plans, he just needed to combine them and get rid of the more combat oriented Gon and Killua somehow.
Togashi is hard to read as a person because nobody is the same person they were 20 years ago and the spouts of Hiatus make the shifts in tone and personality hard to predict.