A few ideas about icicles.

How about adding a mechanic where icicles can break under the weight of a mob/player? I think such a small mechanic would look logical, since icicles aren’t as hard as, say, pointed dripstone.
It would also be a good idea to add a feature where, when the base of icicles is destroyed without Silk Touch, they wouldn’t drop as a loot. We could also add ice crafting from them.