Yep, there was no real reason to remove a TB4 port. Certainly not because of "the SD slot taking up space", there is plenty of space.
Apple have removed a "shared outlet" not a port.
Old MBP - 2 TB3 ports with 4 connectors. You could NOT use 4 lanes for 4 devices (so you could NOT do 4 x 40gbps) - you had a max of 2 x 40gbps "time shared")
New MBP 3 TB4 ports - which you can chose to run as 3 FULL TB3 ports using all 4 lanes for each.
Or you can connect a TB4 hub to ONE - and have extra "10gbps" outlets for your screens / slow card readers etc - and STILL have 2 x 4 lane TB3/TB4 ports. (TB4 is fully backwards compatible with 4 lane TB3 as long as you do not run them through TB4 dock)
My setup
1 TB Port -> CalDigit TS3+ -> Sonnet 10GBe adaptor - (that did NOT work well on MBP Retina if anything else was connected on same side) + external 49" screen + RME Fireface Audio via USB + keyboards/mouse and 3D Connexion Space Mouse + Resolve and Steinberg dongles.
1 TB Port -> high speed CFExpress/XQD Card reader
1 TB Port "free" for what ever.
Power comes from TS3+ unless I do big renders - then I attach the MBP 140w power brick.
I never have issues with network speed (950mbps+) when copying from CFExpress -> my NAS. And I can actually work unhindered on the machine while it is doing so. I can do 8K editing direct on my NAS without problems through the 10GBe Sonnet on the TS3+. But as it is a notebook - I often just dump the files on the SSD - and go and sit somewhere nice for the raw first edit.
The ONLY issue(s) I have is sometimes the Sonnet 10GBe does not like to come out of sleep mode. But a quick whack with a hammer usually wakes it up. (Actually just plug and unplug) - the other issue is the TS3+ itself - I have to run the RME Fireface - the built in sound from TS3+ is terrible and it has very low "charge power" for external devices (max 1.5A/5v)
So in short - the TB4 ports in the MBP M1's gives you much more than the TB3 ports did on the MBP Retina. And it actually work really well.
On the MBP Retina it was hit and miss - and always battle to figure out what ports was occupied by high speed 4 lane devices. Plug in an e-GBP - and BOTH connectors on one side was FULLY saturated during a render. So you could not have the fast external drive on the same side as the e-GPU if your source files was on it.