I
really prefer how much easier internal PSUs make things for cable management, transporting/storing the system, or having to replace the power cord. I recently set up a Wii U again, and it's a nightmare of cables - even with the game pad charging via USB now.
However external power bricks are by far the better solution for things like consoles and monitors/televisions from a servicing point of view.
The power supply is one of the most-likely components to fail, and it's far easier to replace an external brick than replace/repair an internal power supply - especially if it's a standardized component.
A big problem is that most power bricks for consoles are proprietary rather than using standard designs though.
And those power bricks are often junk. Xbox 360 and Xbox One power supplies are huge; have awkward cables; use proprietary connections; and have awful, tiny, annoying fans in them.
I love that the Switch can be powered via USB-C, and DS/3DS via USB (though the latter still use a custom connector on one end of the cable).
Unfortunately that's not going to be possible for next-gen systems, as they're sure to require more than the 100W maximum USB-PD allows.
They're probably too large for a console, but it makes me wonder if server-style power supplies would be feasible:
Internal to the system, but standardized and easily replaced if it dies.
I've been going through an replacing internal PSUs in many of my retro consoles -- Sega Saturn, Dreamcast, Amiga 1000, Atari ST, etc -- With Pico PSUs so I can use external power supplies, because it's way, waaaaay easier to replace a dead external PSU than a dead internal one.
External all the way.
That sounds like a great project - and something which would be of huge benefit for a collection of retro consoles, especially if they are all compatible with the same power supply type after modding.