Robert, it is not clear what your proposal is. Which name do you want to
eliminate?
I've always hated the inconsistent and misspelled names like "ratcoef"
(there is a 'coeff', but no 'coef'), and have also always found it confusing
that there are alternate names at all. Unfortunately, it is the misspelled
names that Maxima treats as basic. I would vote for renaming ratcoef to
ratcoeff.
I'm not sure why you include true=?t (and not false=?nil) in the list. "?"
names are internal and the user shouldn't care about them.
Diff and derivative are a particularly bad case, because derivative is the
nounform of diff. Again, something I've always found confusing and
counterintuitive. The reason for this is, I would guess (RJF, can you
confirm?) that diff/derivative were invented before the noun/verb scheme.
I'm not sure what you mean by "embedded in the code" -- I'd think a global
replace could take care of this easily.
-s