I think if you know what you're talking about, Andy probably loves a good challenge. You're right about the vehicle type for his reviews, not sure how to address that. His driving style and preferences seem (from an outsider perspective) to be fairly pure. That means he's really good at what he does, but as you say it may not extrapolate outside his area of focus. Throw the same tires on a mustang and a C8 Vette and you're right, the results may be wildly different. Perhaps he needs a testing buddy to mirror literally everything he does with his testing, but with a bigger/heavier car.
Not a lot of people would trade back a brand new Porsche GT2 for a Miata (or a 3rd McLaren), but there's Andy still towing the Miata around the national parks...