See, here's my thought process on the subject. Previously, Kishi was writing week to week, and doing all of the work himself, in regards to Naruto's serialization. Very little planning was involved. He was just making shit up on the spot.
Samurai 8 is different. He's had years of planning, and he's specifically only doing the writing this time. Having to only write is easier than having to write AND do artwork AND everything else involved.
My point being, multi-tasking is harder to pull off than just doing one dedicated task. It's for this reason alone that I'm willing to give Kishi the benefit of the doubt in regards to his writing, despite not liking Naruto's writing for the most part.
Also, Kishi gets more free time now to exercise, which he admitted in an interview helps him to come up with better ideas. He enjoys walking, which increases blood flow, which he states directly improves his ability to come up with ideas. And you know what? I think that's perfectly sound reasoning. I too think better when I'm walking my dog, etc.