not surprised at all
I don't think either of them will be #1. What has happened this year is too good for both of them. might win a slam, but will be #3 and below I think.
djokovic and murray will be back. so will stan.
to me, next gen(+) - zverev, kyrgios, shapo, thiem (on clay) seems to have more of the x-factor than weakest gen (nishi, raonic, dimi).
Nishi and raonic will be limited by their injury prone bodies, but still still have some time on their side.
Remains to see what dimi can do - he's played great tennis this year at times - brisbane (beating 3 top players), AO (run to the semi), cincy (win without dropping a set )
then there is delpo who can play spoiler anywhere
and cilic who is a threat on anything except clay (faster surfaces even more so)