Now that I have watched all of Lupin the 3rd series 3. I can agree that the character's design improve towards the end of the series. I know what bothered me about Fujiko's design so much. It was her eyes. They just looked strange. Especially the bottom lashes. It looked like she was wearing too much mascara and got "spider eyes". Goemon also looked poorly designed. His face looked weird. About halfway through the series they started looking better. I don't know why Jigen has brown hair in this series. In the other 2 his hair is black. Lupin's face looked goofier than usual in this series. The character design of the other characters not the main 5 looked simplistic and most of the women looked the same. They just had different hair. Some of them looked a lot like Fujiko (and they weren't her is disguise)
The episodes were in my opinion hit or miss. I either liked them or thought they were boring. Some were really funny though. I really liked the episode "A Cocktail Named Revenge"(episode #30). It's very Hamlet-esque.