If you think you can make a better sender than bCNC, I think the community would be excited to see it. In my opinion bCNC is the best sender out there right now, and its certainly far from perfect.
On the interpreter/machine control, there are a bunch of mature projects for a bunch of different micro controllers. I don't think you'd find much enthusiasm for yet another one, on yet another platform without having some pretty enticing features. It sounds like you may be overestimating the need for speed in a machine controller. Keep in mind that professional CNCs for the 90s worked better than most current hobby level machines on ridiculously slow controllers. I've been running GRBL on piddly ATmega328P for awhile now and it is plenty fast enough.