should not?
why?
there is no reason it can not be made to be “non miserable”.
For the same reason that, although it's physically possible to put a Ferrari engine in a Dodge Dart body, it's not going to work. You can't make the Dart use the power of the Ferrari engine without a total redesign of the body.
Putting a full-blown OS in a tablet -- AND making good use of its capabilities -- would require a redefinition of "tablet" such that it would start looking like a PC. You will have come full circle and rediscovered why there will always be a need for full size personal computers.
Tablets will reduce the PC market considerably, but they'll never wipe it out.
Manipulating tens of thousands of lines of data, building very complex financial models, writing and testing VBS script for macros, creating and editing PP presentations that are hundreds of pages on a 9.5” screen is not a good plan. There is a reason my workspace has dual 22” monitors...
Some light work (viewing, light editing, simple creation) doing these is fine but heavy duty stuff belongs in a different environment.