It was only a few years ago when I was the only one without an rtg based amiga system amongst my group (of about 20 of us). I really think you underestimate how many people have things like a grex, a prometheus, a mediator, are using zorro slots, using isa slots, using a p5 gfx card and so on. I also think you vastly overestimate C vs. asm. A quick glance at aminet at any time in the last 5 years shows that asm is a minority language. Performance between code generated from a good c compiler isnt massively different to that written in asm, although the quality of the code is down to the coder as much as anything.
And Im absolutely not missing the point youre trying to make, but what you seem to be missing is that just because its new, doesnt mean it'll be reliable. As for compatibility, is 100% the actual target? Once upon a time likely compatibility was being touted at about 30%.