Just hope:
1. SSD upgrade pricing isn’t a giant f-u to customers.
apple just cranked the RAM update on the MBP 13" two port from $100 for 8GB to the more uniform across the product line up $200 for 8GB . Unless Apple changes SSD pricing across the whole line up ... it will probably be abut the same $400/TB pricing. Most likely iMac prices will creep higher just like the Mini prices did. Apple may keep an "educational", non-Retina Mac around (and perhaps won't be quite as kneecapped as it is now. )
What could see in the iMac that it gets the iMac Pro ( and Mac Pro) like NAND blade design so that at least the NAND storage could be replaced if it fails without replacing the whole board. Apple would also get to use the same subcomponent in multiple Mac lines ( more volume ... hence lower unit cost for them. ) . But off the shelf 3rd party upgrades ? No. but repairable is good issue to cover also.
2. Non-soldered and user-upgradable RAM. SSD with T2 will be locked, hence #1 above.
Apple removed the "RAM door" from the 21.5" model years ago and still it is shipping with DIMMs. Soldering DIMMS on an iMac does a whole lot of nothing. It bloats out the logic board space for not much of any material trade off gain. For laptops get better z-height ( "thinner". ). There zero thinness advance to be gained on an iMac. The middle section of the iMac isn't "thin" ( it is only the edges that a 'pruned' thin and the RAM isn't there now and probably not in this future model. )
If Apple tries to thin out the iMac into the iPad Pro like uniformly thin slab then probably should just run away from the device. Soldered or not just a bad idea.
Apple hasn't solder the RAM on any of the recent mainstream desktop models. ( had a small patch off in the weeds for the 2014 Mini but the 2018 put DIMMS back in. ) Not sure why they would start now. Apple hasn't sone any inclination along this line at all in the desktops. Not sure why folks keep bring it up as though it is just around the corner.
3. Emphasize function over form.
Part of the issue with the RAM door is Apple's desire to hide it from plain view behind the pedestal arm of the stand. If just let that go then so-DIMM upgrade on iMac Pro could be done. Ditto the 21.5" iMac. If can't jigger the board layout so the DIMM slots are back there and not trading out fan vent exit space ( again being hidden from plain view by arm-stand. )
4. Lower pricing - this is not the time to bump pricing up.
The HDDs were in the systems only to keep pricing down. Once the HDDs are gone, then pricing is going up.
Apple could get to lower pricing if dropped the cost of something else substantive. (e.g., the CPU+GPU costs came down $100 then a $100 swing up in storage cost would balance out. ). it is a possibility ( e.g., use a AMD solution or get some huge discount from Intel and/or AMD. ) . just not probable if Apple is being relatively risk conservative though.
The RAM stuff is just made up fears. There is some things Apple is on track for that many folks won't like. But you don't have to make up stuff even they aren't out to do to pile on top.
