Others have asked for mobile only Switch, no? Wonder if they could split it into separate, cheaper versions for specific audiences? I guess if the cooperative gaming idea doesn't get anywhere that could well happen, with the controls being fixed. In a clamshell?
Indeed, they could continue to offer a common, interoperable software line but split out the mobile and static hardware. You can still use the same accessories, games etc and still play multiplayer between devices (take mobile Switch to a static Switch house) and use the cloud to sync games saves if you own both.
Switch as it currently is gives them that ability if they so choose. I wonder if Nintendo could end up supporting all "three pillars" (mobile, home, hybrid) from one chipset and one software lineup? Hybrid Switch might be a stepping stone.
Clamshell mobile only Switch might be ale to go fanless after a shrink, and as you say potentially ditch the joy cons. Smaller screen, no dock, no HS&fan, greatly simplified controlls ... $200 in 2018/2019?
Nintendo have options, at least.