hi Kelly



> There will need to be a way to

> handle this gracefully—and more robustly than, say, just asking users

> to prefer text commands.



nobody does this or should do this (or did really even in the past). The 

whole idea of inputenc was to enable the user to use sophisticated input 

methods when available, eg type ä or ® or <you name it>



the whole system works by converting whatever input method to a 

"standard LICR", eg



  ä  -> \"{a}

  ®  -> \textregistered

  ...



all behind the scene. From that point on it could be safely used within 

LaTeX like sending it to the aux file or typetting it as a single glyph 

when in T1 encoding or as \accent ... a when in OT1 or as ...



As a user you thus had a choice of using ä or \"a or \"{a}  but 

internally it all came to the same.



This is very much true also with utf8 now, where you can use the utf8 

characters directly or you could use \text... commands or mixed.

the only restriction with LaTeX is that it checks what fonts you use and 

only sets up those unicode characters what can be represented by these 

fonts and for all others you get an error (not true in luatex /xetex  as 

there theunicode chars are essentially pass-through and just fail in the 

end)



anyway, for history but I think still somewhat illuminating  the whole 

area I recommend my 1995 talk about encodings:



https://www.latex-project.org/publications/indexbytopic/2e-concepts/



of course this is way before the event of unicode or xetex/luatex ...



cheers

frank