I like the spirit of the policy, but do not support only involving NCEA in the last year.
At my high school years 9 and 10 were really unfocused, with the vast majority (apart from the accelerated classes) not caring about academics. With the introduction of NCEA and the credits system it gave a sense that everything 'meant something', and pushed me to try harder at maths in order to get E credits. Without that, I doubt I would have ever got the skills to go into engineering.
Do you like this suggestion?