I took the test in September and also had an experimental heavy section and made a 15 on the BS, so that's the angle I'm coming from.
I found the actual BS to be considerably harder than any of the practice ones, including AAMC 10 and 11. The passages in 10 & 11 weren't really that tricky to follow, and for the most part I felt as though I could usually identify the type of knowledge took to answer a question, even if I didn't have said knowledge.
Multiple times on the actual MCAT BS I had no idea what the question was getting at--I simply couldn't follow the question. It took rereading the question a few times, and then rereading sections of the passage once or twice more, before I was able to have an idea for what the question was pulling at. What's more, there were a couple memorable questions for me where I never figured it out, and made what I thought were good educated answers but that typically hinged on one opaque line in the question or the passage that didn't really seem to warrant the singular attention I was giving to it.
I think it's a mistake to suggest that the results have changed over the years, as the test is normalized so the same proportion of people are going to get the same scores year after year, experimental heavy or not. I also think it is a mistake to think we can generalize the difficulty or ease of any particular test or series of tests from the collection of anecdotes that trickle into the MCAT forum of SDN. There are tens of thousands of people that take the MCAT every year, and this is very much a self-selecting bunch that uses similar preparation and similar guides and with back stories that do not cover the wide range of test-takers. To suggest that past tests were easier, harder, or just as hard based on SDN experiences just doesn't have real justification.
What we can look at are the test materials that the AAMC provides and that the test prep companies provide. Going simply from these materials, particularly the past AAMC tests, I found the BS section on the real thing to be more difficult, more confusing, and more time-consuming than any of the AAMC practice tests. From my experience, I think many people are perhaps downplaying the difficulty too much. That's one test and one person's opinion, take from it what you will.