I don't necessarily have a problem with a 2-tier system. As already pointed out, we already have that in some form, because of the foundation/higher papers. And no one is fooled that an F-grade and an A are in any way comparable, just because they both have the name 'GCSE'. Employers and colleges routinely ask for, say, 5 A-C GCSEs rather than just '5 GCSEs', which is not much different surely than asking for '5 O-Levels'.
Interesting about exams vs coursework, everyone always says what about the poor kids who aren't good at exams and need coursework to get their grades up. But some (I was one of these) much prefer to do an exam, and find that suits them better than endless dull plodding coursework.
No problems with the exams being made harder, either. I did mine 15 years ago and found them a bit of a joke, and got 'A's without even doing any revision (no wonder I liked exams!). And I'm not some genius with a photographic memory either. I doubt they've got dramatically harder since then, as the trend tends to be the opposite, so dread to think how much they must be dumbed down now.