I grew up during the heyday of 20+ episode seasons. This season length only works well if it's something like a sitcom, police procedural, or mystery of the week with only loose continuity. And let's not forget the reason for 20+ episode seasons was to quickly make it to the 80+ episode limit to get into syndication. Back then when you wanted tight, focused storytelling you did mini-series which could be as short as 2 nights of 2 hours or even in some extreme cases be week long with hour or two episodes. On very, very rare occasions these would lead to a regular series but those would almost always pan out to be weak washed out shadows of the mini-series.