I usually don't waste my energies by opposing to any changing force that may modify traditions, languages, habits, recurrences, creeds, ethnicity in my country or in any other country.
It's not that I don't care for tradition, in fact I can be quite affected by its corruption on a personal level. It's just that mankind attended the burial of its own traditions a zillion times already: shouldn't we have by then learned that tradition is the illusion of permanence, not permanence itself?
There is no possible reason to get hysterical if our traditions are overtaken, whether a local dialect or a convention is swallowed by a stronger idiom or rite, a cuisine delicacy is replaced by some barbarian branded food. (I am lying: I amterrified by the losses so much I am becoming a conservative).

That said, I haven't the faintest idea why on earth Italy should be attracted by Halloween.
First of all, the pumpkin is not an important presence on the Italian table.
Second, we traditionally celebrate the day of the dead on the second of November, by going to visit our dead relatives at the cemetery. In the early morning of that same day the dead come back to visit their former houses. Why bothering to exorcise any fear of death two nights before?
Third, and most important, there is not a big neighborliness tradition in Italy, at least not everywhere. Attitudes and dispositions strongly change from region to region, from town to town.
For some, who are friendly and intrusive beyond any reasonable measure, the situation is so much amicable and interfering during the whole year that they have no need to emphasize their good neighborly relationships by going to ask for candies on a certain day of the year. For many others though, it's not a good idea to go banging at night on someone's door anytime, especially if cheerfully. They tend to be wary, defensive, uninterested even if respectful of the neighbors. Or just, as it mostly is in the northern Italian culture, sober in their manifestations of cheerfulness.

Near Ivrea, a town between Turin and Milan, two fourteen years old were badly wounded tonight because an old man, that they were trick-or-tricking, shot four blows against them with his hunting rifle. As it seems, he was a frequent victim of jokes and vexations by the local kids. The unlucky wounded teenagers were in fact part of a small gang of kids that threw onto his frontyard some noisy firecrackers just right before going in and knocking on his door.

This sad story gives us two more hints on why Halloween should not be popularized in Italy:
First, going door-by-door may instinctively, seriously be mistaken by the kids for a mafioso behavior, potentially turning the whole thing into something annoying when not actually threatening.
Second (and folks, even this is NOT meant as paradoxical) there's a good chance that in this country Halloween may turn out not as a celebration, since we don't have anything to celebrate on October 31^st, but as a dreadful game.
Hopefully not, but possibly, like this one.