So, on the power side of the equation, I have come to understand why they chose to go the direction they did.
With the previous generation of MagSafe/MagSafe II power supplies, if the cable gets frayed, you have to replace the entire power supply. If the MagSafe connector gets hosed, you have to replace the entire power supply. Basically, if anything goes wrong beyond the AC input side, you have to replace the whole power supply. I ended up buying a whole bunch of these things over the years, so I am particularly sensitive to the amount of money I've spent.
With the USB-C power supplies, if something goes wrong with the cable, you just get a new cable. If something goes wrong with the connector on the cable, you just get a new cable. The only time you need to replace the entire power supply itself is if something goes wrong internally, or if something goes wrong with the USB-C connector on the power supply. And since cables are engineered to break before cable connectors, that is much less likely.
Don't get me wrong, the MagSafe connector has saved my machine on several occasions. But I understand why they want to be able to cheaply and easily replace just the cable part, because that's the part that is most likely to have hardware failures.
I do wish they had figured out some way to have a standardized cable interface on the power supply itself, and a MagSafe-like connector on the other end. That would have been the best of both worlds. But failing that, I think I will grudgingly take the second-best solution, which is to have a standard USB-C connector on both ends.
Now, this whole concept of mixing USB-C, USB-C Power Delivery, and Thunderbolt 3, that's a whole 'nother Gordian Knot that I really wish they had not created.