Yes, I agree that it would make more sense (and be more sympathetic to Sherlock) if he had arranged the phone call about Mrs Hudson to get John out of the way. Rather than it being Moriarty and Sherlock refusing to go and see her...

I agree that the one person Sherlock does care about is John, and that was shown in Hound quite nicely. That's why it is so sad that he's having to put John through all this grieving for him unnecessarily. :-(