I think it depends on what you prioritize? Nishiki was just a brief lunch stop for me, and Gion is just a shopping area.
Or alternatively they could each be half days.
Hmm I think Nishiki/Gion will be a leisure stroll for me. Monkey Park opens at 9AM and i'm planning to leave from my hotel at 8am. total time to go there, spend time and come back maybe takes 4 hours. So from monkey park I'll come back to kyoto station and do nishiki market, gion, and the rest. does that sound good?
The only thing I would say is that if you hit Gion too late, some of the more interesting shops could be closed. But I enjoyed strolling there at night, so it didn’t matter to me. It is beautiful in the evening
I think your plan is definitely workable, though, if you don’t get distracted in Arashiyama. Which I did- there was a doll store and a foot bath I think.plus an interesting shrine.