hosannainexcelsis
Member
First, a brief history lesson. In the earliest days of Japanese animation as a commercial industry, the most prominent studio was Toei Douga. Toei's feature films imitated the style of full, fluid animation found in Disney's animated features, and the studio self-consciously aspired to be the "Disney of the East". The industry was forever changed in 1963 when Osamu Tezuka was approached by a TV station about adapting his manga Astro Boy into a TV anime. Tezuka promised the station that he could produce the anime cheaply and quickly. In order to do so, he could not use the principles of full animation, and so developed the technique of limited animation to get the job done on time and on budget. Limited animation involves not changing the drawing every frame (a.k.a., animation "on ones"), but keeping the drawing constant for several frames (most commonly "on threes"), thus sacrificing some fluidity and motion. This established the expected standard that Japanese animation would henceforth follow down to the present day. Directors and animators developed techniques to work with and take advantage of these constraints to make anime visually interesting (e.g., the stylized framing of Osamu Dezaki's direction, or the strong key-poses of Hiroyuki Imashi's animation). So Japanese animation has found much of its distinctive strengths in the limited format, and moving it to full animation would, besides being impractical, weaken or eliminate many of these strengths.
The most detailed, realistic animation you can get would be in the works of Hiroyuki Okiura (Cowboy Bebop movie opening, Jin-Roh, Letter to Momo). Okiura keeps strict standards for the character animation in his works, and obsessively examines it all to make sure it is as precise as possible. The downside to that is that it requires a long production time - Letter to Momo took seven years to make - which makes it unattractive to production companies. In fact, the recently released movie Miss Hokusai was originally supposed to be directed by Okiura, but his demands for extended length and extended production time were considered too great by Production I.G. and he was taken off the project and replaced with Keiichi Hara.
TV anime is under much greater time constraints than movies, so it requires even more time-saving measures. That's why most TV productions have inconsistent animation - key scenes and episodes are given more time and given to top animators to get the most effort put into them, while other scenes and episodes that aren't as important are sacrificed to keep the overall production moving. More detailed character designs require more time, effort, and skill to animate, which is why anime designs usually lean to the more simplified and stylized side. Plus relatively loose designs allow for a lot of flexibility in individual animators adapting them to their own styles, which you can see a lot of in One Punch Man and the director's previous work, Space Dandy.
So hopefully this explanation helps you to understand why animation in Japanese productions is the way it is. To do what you ask would require much more time than schedules allow, and may not always end up with a better result anyway.
