^^ Not very convenient with the brick under the table. As is you are now going to have a USB-C SD Card adapter hanging out from the back of the computer.
I'm not very keen on having my Ethernet there, either... let alone the whole "desktop needs a power brick at all" thing... and while it sort-of makes sense for people who have Ethernet sockets next to their power sockets (a) that's not everybody - my switch is sitting on my desk, (b) those people have probably already solved the inscrutable problem of running a patch cable up to their desktop and (c) my experience is that having things-plugged-into-other-things around power sockets is a recipe for knots.
I get the impression that M1 - clearly designed mainly for ultra-portables - just doesn't have the spare I/O capability to provide more than two USB 3.1 ports worth of I/O on top of Thunderbolt (or to support more than 2 displays total) so arguing about port provision on
M1 machines is a bit moot. More i/o is one of the things on the 'must have' list for M1x/M2, especially if (as rumoured) the 14/16" MBPs are getting some ports back...
Where the Ethernet is coming from - and how it is getting down the power cable (Yo, dawg, I hear you like Power-over-Ethernet so I put ethernet in your power...) is a bit of a mystery. Given that the Mac Mini quietly gained a 10Gb Ethernet option a few months after launch, will the same thing come to the iMac? Is it a dedicated Ethernet line from the SoC, or does the SoC have external PCIe lanes?
What I'd
like to see is a TB3/4 hub designed to sit neatly underneath the iMac, provide extra ports at desktop-level and (ideally) power the iMac via Thunderbolt and/or MagSafe. One fly in that ointment, though, is that the iMac seems to need a 143W PSU (according to Apple specs) and I believe that Thunderbolt tops out at 100W. Also depends whether the Ethernet comes down the power cable as USB, Thunderbolt or Ethernet from a controller in the Mac.