As to your edit. Personally, I think Apple kind of backed themselves into a corner with this product's naming. It's not a huge deal and it's something that'll probably make sense in a year or two with another shuffle of the models but for this very minute the new MacBook is being marketed as just "MacBook" despite it being more 'air' than a MacBook Air while other MacBook Pros are distinguished with the "With Retina Display" tag that the new MacBook doesn't have despite it being essentially a MacBook Air With Retina Display.
As things currently sit it would make more on-paper sense for the MacBook Air to be called MacBook, and be presented as the basic, entry-level, moderately flexible, mainstream Apple laptop. Macbook Pro as the more flexible more powerful option and Macbook Air (12") as the ultrabook.
Maybe that's how it will end up in a year or two.
As to the single port. I mean, it's not for me and I tend to think Apple maybe went too far with this, but I can somewhat see the usage scenario they probably had in mind. I think they conceived of this machine to be used basically how an iPad is used but without being an iPad. Framed like that, a single port makes somewhat sense with the assumption being that 95% of the time you'll be using it unplugged and whatever you might need to plug into that port will likely be something like a drive that only needs to use that port for the time it takes to transfer whatever and you're on your way.
Of course being a USB-C it busts compatibility with existing USB 3.0 devices(which, side-lol but remember the huge spat people made over Apple 'breaking' iPod cable compatibility and now this happens...) so that's unfortunate no matter how you slice it if you have a lot of USB devices already, but this is a state of the industry change ultimately and before long I have no doubt USB-C will completely supplant conventional USB.
Fact of the matter is though, for that to happen we need products like the MacBook to aggressively push for that without hanging on to legacy. Just the simple fact that this is Apple and it's a high profile release and there already exists a cottage industry for making Apple accessories and adaptors and the likes will alone influence the creation of more USB-C peripherals. Don't think it will be long before it's effectively replaced conventional USB entirely.