As far as I know it's not the HCl that is the problem, it is just that the compounds themselves are to some extent caustic or dehydrating to the nasal membrane, freebases being notoriously more caustic.
But amphetamines and coke seem to be significantly more damaging than ketamine while normal amphetamine is usually the sulphate salt and coke and ketamine the HCl salts. My guess is that making something like ketamine phosphate or tartrate of fumarate would not help all that much, perhaps just a little.
But all of these organic compounds are in some way reactive at least at an ionization level (pH) as opposed to inert stuff like sand, glass and many plastics. Then there is the mechanical damage, I can see sharp crystals doing harm if they are not crushed properly.
I wonder how bad heroin is for the nasal passage, or a number of pharmaceuticals? I have snorted things that were very soft to take like modafinil. Although the amounts are pretty small for that.
Snorting too much of anything is probably a bad idea but I would still be interested to hear what psychoactive drug would do the least damage when snorted. To the nasal passage at least.