Next week is going to be painful, lol.
SpoilerA lot of people are assuming that Mary will get the ax given her relationship with the Big Bad and canon, but I wonder if it'll be Mycroft instead...S3 has been very Mycroft-centric, with us seeing even more of his and Sherlock's complicated relationship that runs even deeper than either of them like to let on. Despite what he likes to say, Mycroft dying would tear Sherlock apart almost as much as John dying...Mycroft has been there from the beginning and he understands Sherlock in ways that John doesn't.
But, it might be Mary, which would be utterly heartbreaking given how fantastic her character has been so far. Too fantastic, in fact, which makes me worried...so few people are that much of a hit right off the bat.
Either way, it's going to suck for everyone all together. It DOES sound like Moffat plans a S4, so one would hope that he might delay Mary's inevitable demise a little longer.