i have to say i prefer this system,and its strength is borne out by your second scenario.
previously
rider a,could win all five races,and his semi and then come second in the final and find himself 5 points behind,rider b,who scores 7 in the qualifiers,scrapes through to the semi's,where an engine failure presents him with a place in the final.
rider a, 3,3,3,3,3,3,2 =20 points
rider b, 1,2,2,1,1,2,3 =25 points
personally regardless of who wins gp,and who scores most points,i think this is a much fairer way to go.
all we now need to do is come up with a system so the farce that transpired in heat one doesn't happen.
now what would have happened in the much maligned elite league??