Student abilities/interests vary: we need an elite education to produce top scientists, a standard tier, and a minimum
The future of our country demands top scientists and engineers who can push forwards the boundaries of knowledge. It also demands a core of solid, well-educated, generalist scientists/engineers. Probably also a certain level of mathematical and practical science skills for all.
No future educational plan can be a one-size-fits-all solution, nor can it pander to politically correct ideas that would sacrifice excellence for conformity, or sacrifice the competitive will to better oneself on the bonfire of the mythical/hypothetical 'level playing field'.
What we need to do is identify those with abilities and interest to match and ensure that they receive the best-in-class education. Allow others to receive a nearly-best-in-class education, and ensure that fixed standards are set for others.
Assessment needs to be a combination of examination, practical activity and language-independent IQ testing. Students need to have the threat of failure, in which case remediation needs to be available. Above all, the system should be transparent and fair.
David M commented
Many thanks for these thoughts, Ian. It would be good to know what lies behind your conviction about the nature of assessment.