- It is most certainly true that universities regard certain A levels as more important than others, and this is a fact made clear to students while they are choosing their A levels. That means that whether or not Ofqual are correct and there is no such thing as "hard" and "soft" A levels is completely irrelevant. If the universities believe that there are, then it's game over.
- Whilst on the subject of "hard" and "soft" subjects at A-level, though (leaving aside the alternative qualifications, and all things being equal I would rather keep those if possible, and don't find it at all surprising that the Tories don't), it seems very hard to believe that it can be said with certainty, by Ofqual or anyone else, that they are standardised. This is mainly because I don't see how they could be standardised. The skills required and marking methods applied vary so much it is difficult to believe they can all be considered level with each other. Obviously this may be ignorance talking, Ofqual might have an incredibly impressive method of comparison that I simply can't conceptualise, but I tend to doubt it. Certainly in maths, classes in our school who took maths and statistics consistently scored higher than those who take maths and mechanics, a pattern which had existed for some time before I arrived at the school I taught at, and continued despite having the least experienced teacher (i.e. me) handling statistics, and a ferociously competent former HoD on the mechanics side. There's also the fact that we were told in no uncertain terms to warn every applicant for maths that more than any other A-level subject their grades would drop compared to how well they did at GCSE. It is by no means unheard of for students to complete their A-levels with maths as their highest grade, but statistically speaking, that really isn't the way to bet. 
- Whilst wondering about how well Ofqual can possibly judge similarity of difficulty across the board, I'm going to embrace totally the fact that they've said (along with Ofsted) that there is no evidence of "dumbing down". This has been a bugbear of mine for years. Partially this is because I've seen a number of syllabuses from various years in my time, and what is immediately apparent is that they have grown more coherent, with topics feeding into each other and building upon each other far more than they did in the past. That has made understanding easier, but that isn't dumbing down, it's imparting knowledge more sensibly (and more to the point, artificially raising the difficulty of the exams to compensate would be ridiculous). More importantly, though, the reason this stuff pisses me off is that there are three variables to consider here: exam difficulty, pupil intelligence, and teaching competence. The third is always ignored in this discussion. "Either the exams get easier each year, or the kids get smarter" is an easy formulation to make (of course, from the perspective of A-levels the latter could be objectively true if seondary school teaching is improving, which I would argue it has, at least to some extent), but the truth is that compared with secondary school teaching, the syllabuses that A-level teachers work from are subject to remarkably little fluctuation, at least in subjects that are well established. Whilst GCSE teachers are constantly being knocked around by the latest new initiatives (some of which, to be fair, are good ideas, a few of which even work in practice), an A-level teacher has the opportunity to deliver almost the exact same material in the exact same way to students who have been admitted to the course using almost the exact same criteria. I have no evidence to prove that this is what is happening, but the argument that this situation means it is to be expected that marks will improve each year is at least worthy of some consideration. A more major overhaul to the syllabus would almost certainly see a drop in results, as teachers get used to the new material and how best to impart it. As I say, the fact that this theory is possible doesn't make it true, but hopefully it makes the point that the third variable should at least be considered.
- I think some of the proposed plan might well be a solution looking for a problem. In my entire life I have never met anyone whose choice of sixth-form college was based on more than looking at one or two options, and then choosing the closest and/or the one most of their friends were going to. The only time this dynamic changed was when certain subjects were unavailable in one place and available in another, a methodology the Tory plan would arguably make harder, since the highest rated subjects under their system are the most commonly taught, which means keeping the subjects around that might actually have affected a choice of school will be less desirable. Unless someone can show me that there are significant numbers of students shopping around for quality sixth-from teaching in specific subjects, then I'm not sure what good the measure will do for anyone but the universities, who already have these things called "grades" they can look at. I'd also like to see some evidence that there are schools using "soft" subjects to boost their scores to the point where their maths teaching looks good when in reality it's shit on toast, and that moreover this isn't trasparently obvious to the local population.
- The Tories are absolutely right that focusing on the C/D borderline takes up a disproportionate amount of time, at the expense of other children. It's almost as though a league system leads to schools trying to get high in the league. If the Conservatives can offer an alternative metric that involves no numbers or categories (both of which immediately lead to focusing on getting as many children past those number or in or out of those categories), I'd love to hear it. Not that it would make any difference, the very nature of teaching is that some pupils are focused on more than others, whether they be borderline students or borderline sociopaths. It isn't fair, but there it is.
- As a former comprehensive school student and descendant of a long line of socialists, the problems with attempting to link a school's worth with the universities their pupils go on to study at is immediately obvious. It would, in fact, entrench the problem of class bias in university acceptance (which as I understand it most certainly hasn't gone away), because the argument "if X is such a good school, why does no-one from X ever get in here" would stop being just sophistry and start being sophistry with a stamp of governmental approval (the fact that said government would be the Tories is no fucking surprise).
- Finally, I am sympathetic up to a point with Smithers' argument that we should just scrap the league tables, because of the damage they do for all sorts of reasons. What I do worry about it what would happen once they were gone. I'm not sure it would lead to teaching being any less of a political football; it seems more likely to my mind that it would simply become an even less well-informed debate than it currently is (if such a thing is possible). I'm also aware that whilst the teaching profession includes a great many people of tremendous talent and dedication, it can't be claimed that everyone is sufficiently self-motivated, and perhaps some form of external pressure isn't actually a bad idea. Whether that could still be effectively provided by Ofsted without the league tables isn't something I'm sure on at all. My point, though, is that granting schools greater autonomy isn't necessarily a great idea, even though each individual school probably thinks it is.
So there you go.
 Typing that reminded of the old "art student" vs "science student" debate that was endlessly bandied around whilst I was an undergraduate (well, it was bandied around by the science students, most of the art types were still in bed). An uneasy truce was formed by agreeing that it is both more difficult to fail or to excel in art subjects, allowing a much easier ride for the coasters, and a mountain to climb for those who wanted to reach the top. Whether this theory is true of A-levels (and I'm not sure how true it is of universities) I don't know, but one hopes Ofqual has a more detailed way of considering the situation.