These chests are only really giving me what are in the personalized trick-or-treat bags (which are bugged within Lion’s Arch now by the way), along with a few slivers. I feel like these are leaving people with less than what they got out of the black lion chests.
Personally, I am really interested in picking up endless tonics. And I feel like this task is the first bit of anti-fun I’ve encountered in the game. I would even be happy with a ridiculous mystic forge recipe for an endless tonic, just so we could have another goal in mind to get there. You could even make this recipe use many, many regular mystery tonics so that black lion chests still must be opened to acquire them. These stories of people opening 1000 chests without finding what they are looking for make me not want to even try, and I know others feel the same.
So please consider this alternative Arena Net. Keep the fun alive.