Interesting chat! I think a lot of things in the Scottish system are good - especially the flexibility on entry, and automatically focusing on a wider range of subjects post 16. However, I thought the "new" AS/ A level system was designed to do that down south too - so you could start doing 4 or 5 AS's, then drop one or two and focus on the A levels in "upper 6th" or whatever it's called now, but would still have the qualification from the single year of AS study. As I understand, highers are basically equivalent in subject matter to an AS, and Advanced highers go a bit beyond A level (according to DH who teaches in uni). So Scottish undergrads with only highers would go into first year, those with AH (most of them in his department) can choose first or second, but most do first, and coast a bit, and those with A levels usually second, just because of the extra cost (plus tuition fees for those coming from England).
I went through the English system, and I have to say I struggle to understand the Scottish one - though I haven't really been through it with DS yet! When I did GCSEs/ A levels in the dark ages, there was a bit more flexibility than some are implying... for example, I did GCSE English in y10 (s3?) which was 100% coursework, then an AS in EngLit alongside the rest of my GCSEs, and I did 4 full A levels (2 science, a humanity and a language) from a state 6th form college, which wasn't unusual. There was a fair amount of difference in the curriculums offered by different exam boards - especially in the non science subjects, which influenced my decision of college, as I preferred the exam boards they used! For example, some language syllabuses were based round literature in that language, others had a big "project", others focused more on conversing/ understanding rather than writing and so on. With any, you'd end up with the same level of understanding of the subject, but the focus was different, and students who'd followed one syllabus would be "better" at some things than others. So 1st year of uni could be bringing everyone up to the same level in everything. When I started uni in one of the science subjects, there were areas we'd hardly touched at A level, whereas some of my peers had done loads, so found it really easy, and vice versa! (Though I imagine the exact topics would be different between different unis too, depending on the interests/ specialisms of the lecturers, even though teaching would be to the same level).
The National Curriculum in England is much more standardised than the CFE, and was arsed around with a lot when Gove was in charge - who seemed to want to ensure children were taught loads of archaic nonsense like in Eton 
. Hence the fronted adverbials, total devotion to Shakespeare from age 7 and Roman numerals... Not necessarily useful, but it does seem a bit more academic from a very early age, and eg Y5 in England seem expected to know more "stuff" than P5, though I don't know about the depth of that knowledge, comparatively.