I've read through this entire thread and I have to say I think I've heard every reason NOT to buy one of these on every single Mac release going back to the lampshade iMac way back when.
(OK, but I don't think Apple has made you use an external power brick for a
desktop machine since the old G4 Mac Mini - I had one of those and it
was a pain...)
In this case, though, the problem is that we haven't seen the 5k iMac/iMac Pro replacement or the "M2" Mini - so for the moment the M1 iMac is as good as it gets with Apple Silicon, so I think we're looking at it from the perspective of "is this good enough to replace our 5k iMacs or do we need to wait?"
I'm OK with the M1 iMac as the new entry-level iMac, it's going to be fantastic for many people - and on (selective) speed tests the M1 gives most of the 5k range a run for their money, but
alongside the 5k it is deficient in only supporting one extra display and maxing out at 16GB RAM... and "run for their money" is incredible for the smaller machines, but isn't much of an upgrade to a 5k iMac if you're looking at a machine to last you another 3-5 years.
Of course, that's an unfair comparison - but right now it's the only one we have. If Apple delivers the goods, and the new M1x/M2/whatever machines offer the same sort of improvements vs. the 5k Intel iMac as the M1 does vs. the old Intel MacBook Air, then the M1 machines are going to start looking entry-level again, premature upgraders will be stuck with buyers' remorse, but we can stop beating up the M1 iMac for not being an iMac Pro replacement .
There's also the worry that Apple are still making design compromises (e.g. external power brick, new proprietary power connector) for the sake of thinness.
A 27" already dominates my desk so can't image what a 30"+ iMac will do.
I agree that a 32" iMac is too big for an all-in-one, but I reckon they could fit 28" in the same size as the 27" iMac just by shrinking the bezels, or 29-29.5" by making the whole thing about 0.5" wider to accommodate a small bezel. Since the '24"' is only 23.5" diagonal (if you read the small print) they could probably sell that as '30"'...
I just watched this earlier today regarding this very thing. If the M1 Mac Mini is any indication, there isn't much limitation if any for the M1 SOC.
My point was actually that there's no sense in people asking for more ports on a M1 machine because it looks like everything the M1 can support is already there. Anything extra will have to steal bandwidth from one of the two Thunderbolt controllers. An M2 could/should change that game.
As the LTT video shows, the M1 actually has a heck of a lot of i/o bandwidth: in terms of Thunderbolt, the two independent controllers give the same TB3 bandwidth as the 4-port MBP. OTOH you need (expensive) TB3 hubs/docks to unlock that
...but the main point of that video was to show that the 10GB Ethernet wasn't leeching off anything else - it
did show that the 6k display* was leeching off anything else connected to that TB3 port. That's one area where the M2/whatever will need to up its game, not for the sake of the M1 iMac, but in order to be not just
as good as the Intel Macs but to convincingly beat them.
Other thing is - sometimes it is about whether you have the boring ports you need day-to-day, rather than seeing how much total bandwidth you can wring out of it for LULZ. I still regularly need about half-a-dozen USB
2 devices connected simultaneously, twice that if I don't want to keep juggling plugs - and while they won't scratch the surface of 100 Gbps of bandwidth, that doesn't mean that they won't work better (esp. things like audio interfaces) with their own, top-level USB port, rather than sharing a single USB 2 stream via a hub. The Intel iMacs didn't do too badly: 4 straight USB ports, plus 1-2 USB-C ports if you don't need external displays/TB3 peripherals mean I can connect the most critical USB devices directly and have a hub or two for the rest. For the new iMac... however you spin it, 2 fewer ports is 2 fewer places to connect things without needing a hub. Again, more about wondering what the M2 will be like than criticising the M1 - which could only add 2 more USB ports by stealing from Thunderbolt.
(* another reason why it's dumb to have to connect displays via Thunderbolt/USB-C when you've got room for a proper DisplayPort socket...)