And not that sharp (mine?) at infinity setting on the sides and corners...
If you don't believe me: OpticalLimits review...or, on TDP, compare it with the 90mm f2,8 TSE.
The 100mm L macro was released right at the beginning of the coatings revolution - one of the main factors for increased resolution development in the last decade. It was also released right when IS was going from a (realistically) 2-stop capacity to a 3-3.5 stop capacity. So it was a bonkers lens at the time. The first (and only) "hybrid" IS system Canon ever released. It added a whole new axis of IS.
That said, in a decade, some similarly-focal-lengthed lenses have come out that are sharper. A large number of 85mm options in particular. But I don't know of any lens that is macro and has decent IS at macro use that is as sharp as this lens. For hand-held macro, it's still unbeatable. I know because I continue to waste money buying alternatives, trying them, and selling them.
When I shot Sony, I found that adapting the Canon 100 L was the best option, even with super sharp lenses such as the Sigma (AF was pretty bad).
All that said, the Laowa/Venus stuff that has been coming out has been fantastic. The probe lens; the 15mm macro; etc. Totally innovative and useful stuff. But not a 100mm with as-good IS or AF.
When Canon does settle on a design, it'll sell a boat-load. When they launch a super-high-resolution body, that might be an auspicious time.
One last thing: I think the communication between lens and camera that allows canon to get 7+ IS stops is going to really be remarkable in the macro use case. Eager to see. -tig