I totally agree with you! I've noticed this in a LOT of series I've been watching...the longest being Sailormoon, but uh...who watches that anymore?

So, I'll use Rurouni Kenshin as my example. There are many secondary episodes that are completely rushed-looking and extremely not well drawn, and they are the secondary episodes. My thoughts is that they leave the secondary episodes to another staff and also rushed it to finish the series. I'm not sure if anyone here seen the anime The Big O, but for some strange reason....I've never found any of these flaws in this series. It's only 13 episodes so far, but there are even some secondary episodes, but they don't look so bad. I guess, sometimes the main staff are lazy too, so they leave the secondary ep. to the other staff, just so they won't have to draw such superb drawings for these "measley" episodes.