I totally get this. I use a Slim on Level 8 or 9, and a Red Tip seems pretty mild to me. If you like really aggressive razors, Gillette can be hard to love.
The one factor people haven't mentioned is setting-creep. I haven't experienced it myself, but I've heard stories from people who get frustrated with an adjustable whose setting dial moves too easily. Obviously not an issue with a switchable base plate.
I do dislike having expensive base plates I know I'll never use. ATT, Rockwell: I'm looking at you.
My biggest shaving regret, Charles, is not being able to dial in either of my birth year razors, both 1956 Red Tips, to get a close shave. (Well, maybe my biggest shaving regret is not using aftershave until I was 57 years old, but I digress...) One of them was acquired cased, and seems to be NOS. When I bought it, my plan was to use it once a year, on my birthday. Maybe I'll try again next year...