For some DSP-ish sort of processors I think it doesn't make sense to have addressability at char level, and the gates to support it would be better spent on better 16 and 32 bit multipliers. ::shrugs::

I feel kind of ambivalent about the standards proposal. We already have fixed size types. If you want/need an exact type, that already exists. The non-fixed size types set minimums and allow platforms to set larger sizes for performance reasons.

Having no fast 8-bit level access is a perfectly reasonable decision for a small DSP.

Might it be better instead to migrate many users of char to (u)int8_t?

The proposed alternative of CHAR_BIT congruent to 0 mod 8 also sounds pretty reasonable, in that it captures the existing non-8-bit char platforms and also the justification for non-8-bit char platforms (that if you're not doing much string processing but instead doing all math processing, the additional hardware for efficient 8 bit access is a total waste).