Not the guy, but I think the characters weren't really the problem.
Sure a lot of purists cried fowl when they saw hardboiled Zenigata fucking Fujiko on his desk, but I thought it was an interesting AU and enjoyed the butthurt.
Lupin isn't even that different from his original characterization in Green Jacket.
My big problem with TWCFM is that it raises a big fuzz about Fujiko's apparent origin and then pullen a pointless cop-out.
So they were basically too chicken-shit to change anything substantial or even touch her backstory.
Some might say that Okada was trying to subvert our expectations, but that really isn't how it came across.
Some really fun self-contained episodes though and at least it wasn't a snore-fest like the Italian adventures.