Of course, it is situational, yes...
Then it sucks. I am sorry, and I realize how hardline and on the face of it, absurd, it sounds, but trust me from EVERY SINGLE FAILED ANTI-PROJECTILE MOVE I HAVE EVER DEALT WITH has colored my impression, it is true. It CAN'T be "situational", because it always, in turn, actually never covers the last necessary situation: the one where the character inevitably can't answer easy projectile zoning. Imagine there are different ways to zone: projectiles, good normals, spacing, reversal, et al. Thing is, anyone who has ever had an anti-projectile skill tends to be overly vulnerable to projectiles to the point "spamming" is far too valid a tactic considering its generally considered the anti-thesis of skilled zoning play. Problem is, that spamming only needs to work enough to still hit the opponent some of the time, due to the danger of damage and hitstun. Any anti-projectile move that doesn't cover ALL of it is basically not even a half-answer: it gets backed into a non-answer due to the interplay.
You want a good anti-projectile move? Growler Field from Azrael in Blazblue. I know its been brought up before for Dorf, and thats because IT ACTUALLY WORKS. Why? So long as it is up, a projectile gets absorbed. And its second feature, storing a shot and converting it to a one-time projectile for Azrael, is good because it beats just about any other projectile in speed and outright kills them, not even "clanking". Trust me when I say this doesn't keep Azrael from being zoned, as there are the other aspects and clever projectile usage. Rather, it punishes the "camping" style of zoning that most people pull their hair out over.
Admittedly, the idea of riding forward on a hover-reflect DOES sound intriguing, but I can say that even moving forward anti-projectile moves, often derived from either the Zangief classics the Banishing Flat or Spinning Lariat, tend to fail because of recovery. And those are in games where the speed of projectile and quantity on screen is nothing like it can be in Smash.
Don't forget, Dorf doesn't actually much problem with some of the heavier but slower projectiles. He is as capable as anyone as avoiding a misplaced chargeball, and his wizkick and other attacks can get around "medium" projectiles fairly well through clanking. So either this needs to answer things like the falco laser which he currently can't, or it adds exactly as much as old nB did to his toolset.
EDIT: AND NOW, let me clarify: I will eat my words and then some if I am wrong. This is only because I have been on the short end of the stick in other games where the heavy can be camped enough that I am fairly familiar with the phenomenon, but that doesn't mean this can't be different. If you really think that we can learn to use it so it becomes a legit answer to the projectiles we have problems with, then I will try to withhold judgment till someone with for more ability than I can say one way or another. Its just... I've seen this before, and it looks awfully similar so far, not just as being used now, but including some of the theoretical usage.