It’s a good point - they took the original close friends relationship from the books and just gender flipped one of the characters, making for an interesting dynamic. They also gender flipped Moriarty and had her fall in love with Sherlock which was an intriguing idea given their games in the book.

apparently the pair has always held underground gay icon status in the UK. i didn't discover that until recently. it's understandable, since that's more or less exactly how same sex romantic relationships were portrayed in 19th century literature, in pretty much every european language.