I'm not sure how much better you could expect it to get. It complies with the existing standard and reduces the footprint substantially. Everything the designer set out to accomplish.
I also really like how it turns into it's own standard when collapsed and paired with the splitter.
There's a good chance that if Apple considers it a big enough problem they'll redesign it from scratch. But some less-original laptop company may want to try it just for having an edge. Especially for smaller ~10" laptops.
I'm not convinced you can make the mechanics work when you add the electrical connections in. They only appear to have solid models which don't work, with animations of them working.
Neat idea though. 13 amp plugs are a real pain. The only thing which is "good" is that they're the same size as power supplies, so multiple PSUs on a multigang extension lead don't block other sockets.
The rotating part needs two sliding contacts both safely enclosed and able to carry up to 13 amps.
Ever played with a Scalectrix set where the sliding parts on the controllers spark and give off ozone? PC Speakers where the volume adjustment crackles because the sliding connection isn't very good? Variable resistors that don't vary smoothly? Switches that have stopped switching properly?
Moving contacts aren't as reliable as one solid piece of metal.
I like the idea; I hope they can make it workable, but I'm not sure it's such a big improvement on the existing travel plugs they demonstrated - with the folding pins.
Currently a split plug is in use in the UK (eg with ADSL router-modems) where the pins separate from the plug body. These require a sliding connection of the form needed here. They use a strong spring to ensure firm contact. I don't think this is a great barrier to production of the plug.
That mechanism is designed for contact to be made once. Not every time you plug it in. Also, there's no rotation, so the spring can be made stronger for a better contact.
The sad reality is that I don't think it is enough better than an existing plug to warrant the effort.