It all sounds like a great pick-up, and in many aspects, it is, but did the Chiefs really need to branch out and hire someone new?
The answer seems like a quick-fire yes, but one could argue that there is already considerable pedigree in the coaching ranks.
Tabai Matson would have been the leading candidate in the eyes of many. With considerable coaching experience at all levels, including as an assistant with Fiji and the Crusaders, Matson has been in the Chiefs environment since 2018 and would have surely benefit from a head coaching role if it had been offered.
Neil Barnes, also an assistant coach at international level with Fiji, has a strong knowledge of the inner workings of the Chiefs forward pack and has been instrumental in the development of several players, such as Angus Ta'avao, Luke Jacobson, Lachlan Boshier and Aiden Ross.
Then there is Roger Randle with his handle on the backs attacking game and coaching experience with Waikato, the ever-growing coaching CV of David Hill who has already had time with the All Blacks, and the intricate player knowledge that resource coach Andrew Strawbridge possesses.
The stock is certainly there, but the unknown factor in this conversation is for how much longer are Matson and Barnes, in particular, going to be involved.
Both are long-term assistant coaches across a range of different sides. They may not want head coaching roles.
Chiefs CEO Michael Collins has continued to remain tight lipped about the future of all the assistant coaches but had declared in November that planning for the interim head coach for season 2021 would be a joint process between the Chiefs and New Zealand Rugby.
Bringing in McMillan for 2021 could point to shake ups in the assistant ranks and how he works with Gatland in what's being described as a "shadow-watching" role over the course of the next few months will be intriguing.
• Michael Pulman is a freelance writer based in Hamilton