Volt Strike costs 229 mp, which is a lot. By comparison, the only blood pacts that cost more than this have a valid reason that they cost so much:
Hastega II - 248 - Very powerful party buff
Pavor Nocturnus - 246 - chance to kill a monster instantly
Level ? Holy - 235 - chance at extremely high aoe damage
When we compare Volt Strike to the other newly added Rage pacts, it's obvious that the other rage pacts weren't added for pure damage. They cost less mp than other comparable pacts, and do less damage. To me, these pacts are simply ward debuffs in disguise (i.e. burn, and slow), so their low mp cost with their low damage is fitting.
Crag Throw - 124 - less mp and less damage than mountain buster
Conflag Strike - 141 - less mp and less damage than meteor strike
So now comes the million dollar question: Why does Volt Strike cost so much, and yet only does damage similar to level 70 physical pacts such as Predator Claws and Chaotic Strike (that cost 164 mp), and only has a stun duration similar to Chaotic Strike? Here's a few potential reasons for this which I've done minimal testing on (the results so far haven't yielded any higher damage numbers):
Is it guaranteed to critical from behind a mob?
Does it do more damage if Ramuh is buffed with Rolling Thunder and Lightning Armor?
Does it do damage based on pet TP without consuming it?
Is it perfectly accurate? (definite no, people have seen this whiff)
Does it have a T3 skillchain property? (definite no, Volt Strike -> Volt Strike doesn't skillchain)
Does it deal lightning damage like flaming strike deals fire damage?
If a community rep could help us out with this too, that would be awesome