The commission, headed by former Wada president Dick Pound, recommended that Russia be suspended from competition and barred from the Rio Games unless it entirely overhauls its approach. It also claimed to have found "corruption and bribery practices at the highest levels of international athletics."
Willis said the report mainly provided verification of the investigative work by German journalist Hajo Seppelt, .
"The important thing now is what is going to be the IAAF response and from what I have read they have 48 hours to act swiftly," said the 32-year-old Willis, who won the Olympic 1500m silver medal in 2008.
"In my opinion, they have two options. They can try and take this hit as best as possible and keep on going on protecting their image, playing crisis management so to speak.
"Or they can go 'look, we're totally messed up, this is a totally messed up system and we need to break it completely down. We're not going to be protecting anybody who we've protected in the past. We have to re-earn your trust again.' I hope they choose the latter."
When asked if Russia should be banned from the Rio Games he replied: "Absolutely."
Willis, from Lower Hutt, said he found it "troubling" that Russia was not being automatically punished, and offered a compliance option instead.
"To paraphrase what they were saying, there was hope for inclusion rather than exclusion which is very troubling to me," he said.
"There should be punishment put in place, to show we are not going to put up with this. Even if they do become compliant, there should definitely be a ban or suspension still put in place.
"It is hard to trust that Russia will genuinely try to produce a clean playing field. And all those athletes will still know how to beat the system.
"Even if they do come off it, the benefits of the drugs they've been taking don't suddenly go away. Scientific articles prove the benefits can last for years.
"If Russia suddenly said "we'll be good boys" I would find that something I wouldn't trust at all."
Willis actually hopes that Russia fights the report, forcing the IAAF to take tougher action.
He said details about Russia's state-backed doping system forcing athletes to cheat if they wanted to progress matched what a Russian Olympic and world championship medallist told him a decade ago.
"Revelations like this come as such a relief to people like me - finally we can air our grievances without fear of defamation lawsuits," he said.
"It is a burden off the shoulders - you say you know these things are going on but you don't really know until it is confirmed and you don't want to be a gossip.
"But you've got to call a spade a spade...when it comes to something you are so passionate about. It's not just for yourself as a fan of the sport, but as a future coach and parent. You want to create something for people to look forward to going to."
