I think the trouble with [mwcard=MW1I19]Piercing Strike[/mwcard] is that it requires 2 actions (quickcast and an attack) and cannot be done at range.
Sure, but on the positive side, an attack costs no mana and the Piercing Strike only 2.
Investing 1 attack action + QC for just two mana total to destroy a BF or WT seems like a great play imo.
At the same time, let's not forget this important bit, it allows you to save up some valuable mana for your next round or your Thoughtspore.
It cannot be done at range, that's correct, but the books I use it in can use it on R3 if necessary, that's only 1 round later than the attack spells can be fired.
BF will get 2 pieces of armor out instead of just one, but that is balanced out by being a much cheaper way to destroy it imo.
Also, just 1 Hurl Boulder or 1 Force Hammer will probably not be enough to destroy the conjuration , so you may have to spend a second action on it as well after all - either an extra spell like Acid Ball ( making the mana cost even higher ) or an attack.
Overall, I'd say the attack spells ( and certainly Force Hammer ) are the obvious and superior choices vs conjurations with 0-1 armor whereas for anything that has 4 or more armor you're probably better off with Piercing Strike - if you have a creature that can lay down a 6-7-8 dice hit of course.
The advantage of [mwcard=FWA04]Hurl Boulder[/mwcard] and [mwcard=FWA02]Force Hammer[/mwcard] is that they are ranged 2 and roll a large amount of dice for just 1 action. Many critical conjurations are protected by their placement in the rear of the arena so it might be worth packing at least one of these ranged smash spells especially in your Forcemaster book where it's only 2 points for a Force Hammer anyway.
Certainly. The 2 Force Hammers are still in my Forcemaster book, it's just that Piercing Strike gives me an additional ( and cheaper way ) of dealing with armored objects.