It's not as though I randomly posted a thread about Withering Boon, like...
Withering Boon: not very good.
I was pointing out the NAME of the black counter, and tacked on "not very good" as an afterthought. I was not planning on discussing it further, although it is not a problem for me to do so. It was never intended to be a "throwaway" line, because the discussion until that point had not been focused on Withering Boon. It was more of an aside. I don't know what you mean by "typical of your posts, that's ALL you say." I think I have explained myself further. But to elaborate on Withering Boon...
Advantages:
1B mana cost is pretty cheap
Low colored mana requirement makes it splashable
Abilities such as regeneration, protection from black, untargetability do not stop it
CIP abilities will not be activated
Disadvantages:
Cannot remove an existing creature, so mana must be kept available
Life loss hurts a bit in a color that is probably already paying life for other effects
Since it must be cast while the spell is being on the stack, it must be in your hand
Cannot deal with creatures that are put into play by means other than casting
There are some other minor advantages (negating "leaves play" abilities) and disadvantages (unable to hit "can't be countered" creatures). But the ones I listed are the most important ones. The advantages and disadvantages are usually easy to see. What is more difficult is determining what decks would want to use it, and whether it is good enough to be used in such decks. Decks that include an amount of blue would favor something like Mana Leak over Withering Boon, so it is unlikely to be used there.
So we must limit our analysis to decks that use black, but do not use blue. Black has become increasingly capable of dealing with creatures that are untargetable or have protection from black, thanks to the printing of more sacrifice removal spells like Chainer's Edict and Barter in Blood. And a lot of black's creature removal spells are cheap, ranging from virtually free (Contagion and Spinning Darkness) to three or four mana, depending on the effect you want.
So, Withering Boon's primary advantage is going to be its ability to negate things like CIP abilities. This is certainly a valid reason for using a card like Withering Boon.
Now the issue is both one of the proclivity of opposing decks to use creatures with dangerous CIP abilities, and the likelihood that Withering Boon would be the best way of dealing with such decks. No metagame is completely saturated with such creatures, and in formats with sideboards, Withering Boon is highly unlikely to be desired for sideboard slots. So, the decks that would have really want Withering Boon would be ones that need to protect themselves from the effects of creatures with dangerous CIP (and on rare occasions "leaves play" abilities).
However, the creatures best known for such abilities are ones that really only replicate an instant or sorcery. Withering Boon can protect me from Uktabi Orangutan, but then my artifact is still quite vulnerable to Naturalize. It can stop an Eternal Witness, but my opponent might just use Regrowth. It can stop Man-o'-War, but not Boomerang. And so, for this reason, Withering Boon's usefulness is limited further still.
However, the specialized role that Withering Boon fits (countering a creature spell of any color without blue mana) has never really been filled by another card (I can't think of any). So it is entirely possible that situations will arise in which Withering Boon is a truly solid choice for a deck's creature removal. For this reason, it cannot be completely discounted.
In conclusion, Withering Boon is typically a mediocre card.
I spent my last post explaining why I said "I never said Boon was crap."
To elaborate on THAT...
I thought I must have given the IMPRESSION that I believed Withering Boon to be crap. Force of Will Smith pointed out that it can be used against large creatures (and can negate their CIP/leaves play abilities too). You explained that it is in a color that doesn't normally have counters. DarthFerret jumped in with the White Knight example.
I am entirely familiar with every one of these concepts. I find it hard to believe that any of you would be pointing them out if you had been given the impression that they were things I was already taking into account. Which is why I think I gave the impression that I considered Withering Boon to be crap (or close to it). So when I said "I never said Boon was crap" it did not necessarily mean that someone else had previously said "Oversoul said Boon was crap." I was using it merely to clarify and not to refute anything.