Well I loved Amanda's piece and I love her portrayal of Mary.
John clearly loved her, Sherlock clearly liked her and she worked for me.

I think they had to do her, because she was canon.
But if they had to do her, I think they just wanted to make her a bit more exciting, to have another strong female character.

Well, that's possibly by default...if the show has ended sooner than expected.
But she was important to Sherlock and John and her story was a big one.
This was a decision made by Mark and Steven and I am happy with it.

I think, Mary is always a problem in film versions. She is a problem in the books, too. She is introduced in "Sigh of Four" in a really interesting way, and we hear very soon that John will marry her. But after that, she is barely mentioned in the stories, and sometime there are a few words about her dead. How can anyone film that? One can only do two things: the first is to omit the part (not really a good idea, for many reasons). The other is to re-invent the character. That is what Moftiss did. And what they did worked very well for the series, at last, although I did not like the idea at first.

athameg wrote:

I think, Mary is always a problem in film versions. She is a problem in the books, too. She is introduced in "Sigh of Four" in a really interesting way, and we hear very soon that John will marry her. But after that, she is barely mentioned in the stories, and sometime there are a few words about her dead. How can anyone film that? One can only do two things: the first is to omit the part (not really a good idea, for many reasons). The other is to re-invent the character. That is what Moftiss did. And what they did worked very well for the series, at last, although I did not like the idea at first.

Well, I have seen many reviews and viewers' opinions stating the exact opposite. That in the end it was the focus on Mary that destroyed the core of the show. My son fed up with her as early as S3. Said her character did not make sense. Extending her part over seven episodes was a mistake in my opinion.

If you look at the Ritchie films - which are far from perfect - you can see how you can create a Mary that is more than a simple plot device without sacrificing the chemistry between the main characters. And in my opinion this is where Moftiss failed. Sadly because on the whole their show is so much better than the films. 
 

This. 

Well really, this is ancient history.
But ok...
I don't know whose decision it was not to tell John and I don't know whether Sherlock regretted the decision.  But he's apologised enough and repaid John tenfold.
I should also point out that in the grand scheme of things:  I am certain that if Jon could have Mary back, he'd be only too delighted to accept what Sherlock did.

The Sherlock fandom can go years without new material.  If we didn't discuss ancient history we'd run out of things to talk about real fast.  

I actually really liked what they did with Mary in S4.  To my surprise, because I was not a huge fan of her before.   Ghost Mary in TLD was particularly moving. 

I don't think Moftiss had to include Mary - it was their choice which stories to cover, and TSOT actually bears very little resemblence to TSOF apart from a few references.  I think it was a conscious choice to do her character, rather than them feeling they had a problem with what to do with her.  TSOF could actually have been done without Mary Morstan for the most part.  They could have made John had a background wife if they wanted, or no wife at all.

They had fun with her, I think!  And I liked it - it felt like a well-rounded story in the end.  Ticked all the boxes as I think I said after TST - redemption, apology, self-sacrifice ... even trying to unite Sherlock and John after death, at least the way John saw it.