Some have called for it to be eliminated entirely but wouldn't it be simpler to just drop the blood purity requirement? Can that be done? Has anyone tried?
Sorry, if this is more r/AskScience but it seemed like the best place.
The second wizarding war concluded in 1998 which means that you have broken the subs 20 year rule and will have to be reported.
To discourage off-topic discussions of current events, questions, answers and all other comments must be confined to events that happened 20 years ago or more, inclusively (e.g. 1995 and older.)
Historically speaking there is no pure blood requirement for house Slytherin. In fact there are a few high profile Slytherin graduates who were the children of magic and muggle couplings. The two most famous of these are of course Tom Riddle and Hogwarts Headmaster, Professor Snape.
There is however a cultural trend which is evident in the Slytherin House to glorify those of pure magic blood, a social stance ingrained in the House's mentality by its founder.
Despite popular rumor, there is currently no blood purity requirement for admission to any of Hogwarts' Houses. However it has been reported that the Sorting Hat's own prejudices may have influenced its recommendations. Whatever remedy exists must hold the Sorting Hat accountable for its actions.
You have to bear in mind, the House of Slytherin includes some of the most noble and ancient houses in all of wizarding Britain, with considerable clout within the Wizengamot. Political cabals such as the old 1970s era 'Slug Club' are some of the most formidable old boy's clubs to be found in Diagon Alley.
You could no more close House Slytherin than the Labor Party could expect to shut down Eton Academy in muggle Britain. It would be a blatant act of cultural warfare within a culture presently still mending the wounds and revelations deriving from the times of Voldemort.
Sources: Greengrass, D. "Political alliances and factions in pre-Wizarding War Magic Britain", Research Paper, Ministry of Magic, 2010.