How does Vital Strike effect weapon-like spells,i.e.:
Chill Touch
Produce Flame
Inflict Moderate Wounds
Acid Arrow
Vital Strike is usable only on an attack action (an attack as a standard action). Not casting a spell.
Your God of Knowledge,
Nethys
Correct but in the cases such as Produce Flame and Chill Touch the attacks are made as separate actions from the spell.
Roll the damage dice for the attack twice and add the results together ...
It says damage dice, not weapon damage dice, so by a strict reading of the rules, you could cast a touch spell, hold the charge and then make an attack action to deliver the spell with Vital Strike.
The feat does require BAB +6, so we're looking at Druid 8 or Sorc/Wiz 12. Unless you quicken the spell, it would take two rounds, so it doesn't even sound horribly unbalanced either. Spending two rounds to do double damage is the same average damage per round, although it does limit the rate at which casters go through their spells. (That might not be a bad thing.)
Even the quickened version is probably balanced. It requires a feat and uses a swift action and a standard action. You could instead maximize the spell, which would do almost as much damage. You still require a feat, but you use a lower level spell slot and don't use the swift action.
Could we get an official ruling? My players WILL think of this. lol