I can see where that would make sense for characters who solely play through Out of the Abyss, because all the characters are in the same boat when it comes to magic items (though if the campaign staff really believes that 'leaving an item on the table' is a valid option for other AL games, I'm not sure why the same wouldn't be true here).
The problem I see is for characters who transition between OotA and Expeditions play -- for those characters, acquiring a drowcraft item is a definite advantage, because now you have an item that you can arbitrarily destroy in order to lower your magic item count and 'win' an item you want. This will not only cause players to contest for magic items they can't effectively use simply to have access to the benefit, but it will likely also convince players to bring Expeditions characters into Encounters in order to get the drowcraft items in order to bring them back to Expeditions.
Again, if the general rule on broken items counting against your magic item total changes so that broken items don't count, regardless of whether they were drowcraft items or not, then I have less of an issue with this ruling, since it puts everyone back on a level playing field and treats all items the same with respect to breakage. I'm just not sure that having a class of items that's superior to other magic items with respect to that rule, and that are only accessible by playing that one adventure (unless drowcraft items are seeded as treasure in Expeditions play as well, in which case, hold onto your hats, folks) is going to end up being a good thing for the campaign as a whole.
I guess we'll see -- I can remember people suggesting that most 5E wizards would be mountain dwarves, since they can wear medium armor and still cast spells, and it doesn't look like that's happened, so maybe my fear is overblown. Still, based on the number of complaints I read about the existing magic item breakage rule, I can't imagine something like this not having a larger impact than anticipated.
--
Pauper
