The Bloodstained Sack is cool, and worth the $3, but I really wish there were more costumes for more killers. I understand that this was made prior to the release of the Shape, Hag, Doctor, and Huntress, but this DLC can easily be updated to add more customization to those killers.
What is good about this DLC: The Trapper's new masks were awesome. I loved wearing them and never wore anything else. Except maybe Iron Chuckles and the best new killer mask. The Hillbilly's scarecrow and farmer were cool too, and I quite enjoyed equipping them. The Wraith's facial markings were awesome, as well as the design it offered his cloak. The WW1 variant of the Nurse was so fun to wear despite how rarely I ever used her.
What is bad about this DLC: When I look at these characters I realize that most of them only have one or two outfits, all in all-- their regular outfits and their bloodied outfits. (I'd count the Black Hare, but come on... it's literally a cheap reskin of the regular hare and nothing else. Plus, the Doctor's secondary outfit choices are literally just more buzzy... his black suit is ALSO just a cheap reskin.) The Bloodstained Sack adds nothing to them.
Suggestions: Add outfits for the more recent killers. For example, give The Shape a paramedic outfit. He wore one in one of the Halloween movies. (At least, my friend says so-- I never actually watched Halloween. You may disregard this if you'd like.) Give the Hag a torn dress to wear, give the Doctor some different clothing items that AREN'T just reskins of his normal skin. Give the Huntress something less centered around his pillager design, maybe more centered around her childhood. Perhaps, clothing that Anna's mother wore?
All in all, I'd give this DLC a 7/10. While it didn't disappoint... too much... it could've been much more and way better.