I think the best objection to that I heard from you. The idea of trying to glue a 1.75mm dia. filament to another filament and how some filaments don't melt to other filaments so well. So the mosaic is really more of a multi color than a multi material when we think about it. But the MMU2S is extremely versatile. It will work with any 5 filaments so long as they are the same diameter. crying about heat up and cool down times at each layer is still the print happening, ya know? But when we are sticking filament to filament we don't get to work with a lot of combinations and are limiting ourselves right out of the gate. The MMU2S is about as good as we are gonna get without separate extruders that can be held at temp and a toolchanger. Which requires a lot more money, space, and power. From where I stand the MMU2S is a powerful contender in the multi material arena. Here are my first 2 prints. They were printed with the LV8729 stepper driver for the extruder set at 1/32 micro stepping. With the 0.9 degree e3d stepper motor this brings me to 1674 steps per mm of filament movement. I still have to try 1/64 and 1/128 micro stepping for the E. But look at the surface of these benchy's, man..