I mean, other than certain plot reworks to make things more coherent (of which there would be MANY) the things I would change would be: 1. Malfoid. Obviously. It just works. 'Nuff said. 2. Put Hermione in Ravenclaw and Ron in Hufflepuff. Hermione very obviously should have been a Ravenclaw, and I think making her so she fails to get her into her desired house could serve as a great narrative motivator for actually being a braver person. As for Ron, making him the SINGLE Weasley in his family to NOT get sorted into Gryffindor would only make him feel more like he's the weak link of his family, but like any true Hufflepuff he would demonstrate his unflinching loyalty. Even makes the point of him wielding the Sword of Gryffindor more poignant in Deathly Hallows, as he basically proves to himself that he's worthy to be called brave. PLUS if this means we're redeeming Malfoy, you now have one member from each house working together to stop Voldy, which is a very strong narrative beat. Even gives you more setting variety, as they could all visit each other's common rooms. 3. Rework the Elder Wand. Harry winning by a technicality about the intracies if wizard disarmament is silly. Instead, make it so that the Elder Wand's full power can only be used by "a master of death" most wizards eventually interpret this as meaning you have to kill the previous owner (especially given the wand's bloody history) but Harry realizes that becoming a master of death isn't about mastering death, but accepting it (it DOES have a thestral hair as its core, after all). Harry is a true master of the Elder Wand because he readily accepts his mortality, and isn't afraid to die, while Voldemort is terrified of it, thus ironically ensuring his ultimate demise. 4. One last tiny change: instead of making Evada Kedavra unblockable, make it really easy to block instead. This allows wizard fights to be dynamic rather than just "bad guys shoot green death lasers but always miss because they have the aim of stormtroopers." The good wizards are trying to stun or disarm while the Death Eaters are constantly trying to maim or injure to prevent the target from blocking the killing blow. If you wanted to make Voldemort extra scary you could say he's so powerful and so skilled with it that his Evafa Kedavra is unblockable, but the spell itself is a bit too OP in my book.