Diagon Alley looks incredible from the pictures I've seen - I absolutely love Ollivanders and Flourish and Blotts (although I am really sad that they didn't include Madam Malkin's). I actually don't really mind the pink on QQS - I'm more confused about the fact that (to me at least) on the packaging it appears as the centerpiece of the set - both due to its shape and size. I had expected that WWW would take that role, and was therefore left a bit surprised that QQS is the largest shop. Although I hope that the eventual Gringotts set rectifies this!
Since the leak, I've been thinking a lot about possibilities for 2021 sets (mainly DH-based sets), and so I've written below some of my ideas - I'd be really interested to hear your thoughts about these!
≈$15 - Battle of Seven Potters - Hagrid's Motorbike build with some scenery, includes Hagrid and Harry, and a Death Eater or two on broomsticks (maybe Snape?)
≈$15 - Forbidden Forest - the remake of the old set with Harry, Voldemort and Narcissa (I don't see us getting a Malfoy Manor Set and it's probably one of the only ways that we'll get a Narcissa minifigure)
≈$20 - Hogwarts battle - Small sidebuilds with exploding battlements and play features; with Voldemort, Harry, Neville and Nagini, a Death Eater (and maybe an Ootp member? Maybe Aberforth?)
≈$20 - Forest of Dean - Small tent build with a couple of trees; with the trio, a doe patronus, and a snatcher or two
≈$30 - Bill and Fleur's Wedding (the compulsory HP costume-themed set) - a marquee build with lots of food and drinks, which displays nicely next to the burrow; with Harry, Bill, Fleur, Ron, Hermione, maybe with Kingsley's Patronus and a character like Great-Aunt Muriel or Elphias Doge
≈$30 - Ministry Escape - with the interrogation/court room (and maybe a floo powder fireplace?); with Umbridge with the locket, the trio in their disguises, a dementor and Yaxley
≈$50 - Grimmauld Place - based on Ootp (potentially), similar design to Privet Drive and the shops in Diagon Alley; with Sirius, Kreacher, Harry, Ron, Hermione and maybe Tonks? Or Arthur? Or Ginny?
≈$70 - Hogwarts Bell Towers (or some other large Hogwarts extension) based on the Battle of Hogwarts, with the Room of Hidden Things, and maybe something like the library or Slytherin common room; includes a brick-built ogre, Harry, Ron, Hermione, Luna, the Grey Lady, Draco, Zabini or Goyle, Molly, Bellatrix, maybe Fenrir Greyback
≈$100 - Gringotts based on DH with the entrance area, a couple of vaults and hopefully some tracks and a cart (don't know how they'll convey the underground aspect though); with a brick-built Ukrainian Ironbelly, a couple of goblins, the Hufflepuff Cup, and the trio in their disguises (and maybe a security guard?)
As much as I'd love them, I don't see TLG doing sets of the Lovegoods's House, Malfoy Manor or Shell Cottage - the buildings aren't really recognisable themselves and what happens there is either very violent (Malfoy Manor) or quite boring (Shell Cottage - apart from Dobby's heartbreaking death).
I'm quite interested to see whether Lego will reuse the new Gryffindor Sword piece from the CMF - it is in quite a few key scenes in DH, but then I can see them keeping it exclusive to Griphook. I would hate to go back to just a regular sword piece though (like in the Clocktower)
In the UK, I still haven't found anything...