I was a skeptic about the olympics, because it seemed we have had some issues leading up to it and throw in some cynicism in there and given how much it cost the taxpayers and how much advertisers were throwing The Olympics down our throat, I couldn't wait for the fact for it to be all over. And I couldn't wait for my week in Germany (heading off tomorrow) where I don't have to be aware the Olympics are even happening. Yes, I am a flipping miserable sod.
But the opening ceremony had my surprised and I enjoyed it overall.
The ceremony was 4 hours long and the part you are describing is just the part of the ceremony representing the modern age and the use of technology. As for the choreography, from what I understand, like in the NHS scene, they weren't actually real dancers but actual NHS doctors and nurses and I don't know if there were professional dancers used elsewhere. I've not really reading into it. We have much better dancers out there.
The entire thing was meant to be about British History and celebrating our own endeavours, which including the history of British music, hence the big medley with those dancers.
Personally, I didn't like that bit, but it does manage to portray the current generation. I think Danny Boyle's aim was to try and have something for everyone and any computer geeks here or computer scientists, they had Tim Berners-Lee. He talked about the invention of the world wide web, sure it wasn't exactly a geektacular presentation, but at least it's a geekgasm. Yes, I have just butchered the English language there. Would have been sweet to see other British figures in the world of computing, but to be fair, the ceremony has a LOT of ground to cover.
I enjoyed the industrial revolution(reminded me of William Blake...and Lord of the Rings, but it seems there's a meme surrounding that now), though I thought it cheesy that it was building up to the forging of the olympic rings. Admittedly, I liked the little James Bond sketch with the Queen and I think like many, I enjoyed the Mr Bean sketch. When they said they were going to play Chariots of Fire, I groaned because it's such a cliched thing for the Olympics that it just seemed too ordinary, then I saw Rowan Atkinson and was pleasantly surprised. It's bean years since I've watched Mr Bean.
The NHS/Storytime villains scene was very weird, but it was one of the highlights for me but I thought it and the Industrial Revolution needed something and that's Pink Floyd, both scenes would have been fantastic with some Pink Floyd tracks playing the background, I am glad they did use Pink Floyd somewhere in the ceremony, but they reserved it for the fireworks. Regardless I think the music they did use worked.
As for Paul McCartney, I stopped watching half way through, the fireworks was the end of the ceremony for me, what I did hear sounded live to me, but it is possible he mimed it, which would have been a shame for his fans if he did. It's also possible there was a delay. I didn't notice, but then I didn't pay attention. I am not a Beatles fan and Hey Jude is not a song I like. However, I am a Beatallica fan (Beatles songs parodied in the style of Metallica) and
Hey Dude(warning: language) for me is an improvement. People might hate me for suggesting it because the Beatles have been a massive influence in the world of music and were talented, but it's really down to me not enjoying their music more than anything.