I agree with this, the PV being added to bolt spells damage being nerfed (which was in the game for many years) was already a huge nerf to spellcasters.

I think burning hands (and acid spit) should ignore PV like most other spells at least. Makes no sense why fire bolt would ignore PV but burning hands wouldn't.

Agreed. Burning Hands is by its nature an elemental Touch Attack and thus should penetrate DV at least, probably PV as well. Any applied PV should at least be balanced to make Burning Hands a feasible and reliable option for casters over weapons in-hand.

With regard to Burning Hands specifically, it may trivialize a particular fight that TB doesn't want to be so easy. Just a guess though.

Would increasing resistance to fire in that fight be a reasonable alternative solution? Or giving that particular enemy resistance to the Burning Hands spell / Burn-proof PV? Rather than rebalancing the rest of the game, I mean.