Well, I'm firmly in the OD&D camp here, and wasn't even aware about these strict interpretations of B/X. However I'm also firmly in the camp of playing by the rules of the game at hand - strict B/X style in this case.

How about moving the issue inside of the game world? Would there be an in character price to pay to magically gain the capacity to memorize multiple spells? Would said characer be willing to pay this price? (probably somewhere on the order of selling one's soul)
CC: @kensanata@tabletop.social

@HeyeBodo@rollenspiel.social I played one of these magic-users briefly in a game. He ended up using a dagger frequently (the "flying dagger" fighting technique, I think we joked about it).
I suppose if someone thinks their magic-user is only useful when they can solve 'problems' with spells it would be unsatisfying, but I had fun with him. His memory after he died made him into a larger than life figure for a time, and I was pretty satisfied with that.

@kensanata@tabletop.social