The assessment was made during the application process for funding of series two, with the assessor being provided a draft script of the then proposed latest installment of the show.
It added: "I also query if there too many villains amongst the cast of characters who are so busy double crossing each other that the moral compass gets lost."
That is normal process for productions seeking extensive NZ on Air funding.
The assessor also noted "an aspect of the core premise - the widening gap between rich and poor in NZ - is not being dramatised in the first three episodes".
The report also said: "While the ratings figures presented were positive - from what I can gather they weren't outstanding."
The assessor goes on to suggest series 2 "might benefit from a greater revamp to the one that is currently being presented".
Glenn Usmar, NZ on Air's head of television, said stringent assessments were undertaken before funding was granted to big-money dramas.
"Money is a factor, as well as us considering if a show is a good idea and that it has the right people behind it," he said. "The idea is to challenge the vision of the originating team.
"We are not always in agreement and the Broadcasting Act means we are not allowed to influence the editorial process, so we have to be all over these things before they get under way.
"Some critics didn't like the first series of Filthy Rich but in the end we were all pretty happy with the changes suggested for series 2."
Filthy Rich has since been a hit overseas and was snapped up by US streaming giant Hulu, which has an audience of more than 12 million Americans.
Writer/producer Rachel Lang, from Filthy Productions, said some of the criticisms from the assessor had been taken on board and the first instalment to series 2 had been changed, with filming already under way.
"Some really good points were made and in the end we rewrote the opening episode of series 2 completely," Lang said. "We don't have to agree with assessors' reports but it is public money at stake and that should be protected.
"We also needed to prove the size of our audience, which we did."
Lang revealed an option to remake Filthy Rich for an American audience, with a US cast, had also just been picked up by the Fox network and international company Imagine TV.
Jeff Latch, director of content at TVNZ, said he had welcomed a "robust conversation" with NZ on Air and Filthy Rich producers about the direction of series 2, following the assessors report.
"We all just want to get the best from a terrific show, which is made by some very capable and passionate people," he added.
