If you open the note-edit contextual menu with a right-click, there is an entry "set all notes to 0 cents".

Ah, didn't know that, thanks.  However this isn't ideal on touch screens, where you don't have a right-click.  I'll type more about touchscreens in another message as PT could be improved in some small ways for it.

Also how about renaming 'reset' to 'restore'?  I think this is more intuitive.

Well, this is intentional: when you reset a preset, you want to recover the original state of the preset, not of the instrument that served for creating the preset - which is also at your disposal anyway, and if needed, the freeze button can restransport zero on the given preset.

OK I can see the thinking, however this would be more obvious to me if the button were called 'Restore', not 'Reset'.  Reset in this context implies removing the per-note settings.

Either way, a dedicated 'Zero' button would be appreciated.  Having to copy zero values via a freeze is too complex & slow.  I often want to quickly compare what a detuned instrument would sound like without detuning, so a zero button is important... or alternatively, an 'On' or 'Enabled' button which can temporarily disable the per-note settings.

However, if I edit a preset which already has random note detunes, and change them, then the Reset button doesn't zero them, but instead always restores the original (stored) random detunes.

Is this deliberate or a bug?  To my mind, a 'reset' should always zero out these types of edits - especially as there seems no other way to zero them all (other than scaling them to zero).