I like this idea and a lot of the suggestions here. I think the best approach would be to treat this as a hobbyist machine for individuals or small teams of homebrew developers who just want to tinker with something new for fun - as long as there are suitable dev tools and it is easy to code for. I do art for Aetherbyte and coding for the PC Engine is painful and long winded.
I can see why a part of the retro community wouldn't care about this - there are many for whom the 'retro' style is not enough if it doesn't come with the specific emotional attachment of the console they grew up with. But for some of us, it's a great 'what if...' scenario. Like 'What if <insert machine name here> had larger sprites/more sprites/a faster CPU etc while maintaining the visual aesthetic of the era, and being modern-day friendly with HDMI and downloadable games.' That kind of thing appeals to me more so than a lot of 'modern-retro' that has big pixels, thousands of colours and throws on visual effects that you could have never dreamed of back in the 80s.
I guess the hardest thing is knowing exactly where the sweet spot is, and this would vary wildly from person to person. Do you go for NES? SMS? VCS? PCE? It's quite a wide range and hitting it right would be important.