Short story: Notch did a no no and rolled back the odometer on numbering. RP4 will only even consider a backport of PR4 to 1.8.1 if IC just can't forward port in like -forever-
Seriously though it's a day by day thing. Check the two developer's blogs and hope. MAYBE getting the good stuff working in 1.0.0 won't take that much time; it's possible we could get lucky. Possible... but I'm not holding my breath.