# What should go into \textfont1

    This presents us with a problem: one scheme allows the LaTeX user to
say $$\rm\bf\sigma$$ and get a roman bold sigma, but the other
produces better spacing.  Should a font standard aim to support
logical markup, or beautiful typesetting?  The answer should be
both', which means that in practice the answer is probably
compromise'...
In principle, I would suggest that getting the right output is more
important than having logical markup.
People are willing to have to do ugly things to get the right output in
uncommon cases, but they are totally frustrated when a program cannot
produce the right output with any output.

I suspect that sufficiently clever macros can make almost any input form
work.