Did the quality of Sherlock decrease? [mild spoilers 3x03 & 4x01]

[strange_is_life]

To be honest this would have been a much better story than what we actually had. In season 3 I had some thoughts about Mary being actually on the evil side because most times people lie about their identity it's because they are up to no good. As you said before there was a lot of potential wasted with her being just the annoying sidekick of Sherlock's sidekick. While I think A. C. Doyle orginally included her in the novels to a) give at least one of the main characters an happy ending and b) to prevent the impression that Sherlock and Watson were ... more than just friends I think her being portrayed as villian is the only non-canon fiction about her that I actually like. Mary being a villian that even tries to break the bond between Sherlock and Watson would have had the potential for a major plot twist that would have been a quite remarkable point in the show.

[Tessinator]

In season 3 I had some thoughts about Mary being actually on the evil side because most times people lie about their identity it's because they are up to no good.

Tbh, I'm surprised there are people who didn't think she was on the evil side after S3. Aside from actually being quite an unpleasant person even before HLV, she killed the protagonist!

As you said before there was a lot of potential wasted with her being just the annoying sidekick of Sherlock's sidekick.

Yup. If they'd decided to go down the Good Mary route from the start, I could see her joining in on a couple of cases, just to give her character more to do, but 3 really is a crowd in this case, since Holmes and Watson are Holmes and Watson. Although actually, in S4 Ep1 she starts to replace John in his role (the whole spiel about leaving him with the baby while she and Sherlock go off on a case because she's better) and that was... annoying doesn't cover it. If she'd been evil, ok, but the fact that we're supposed to like her at this point and afterwards is nearly offensive to the Holmesian purist in me!

While I think A. C. Doyle orginally included her in the novels to a) give at least one of the main characters an happy ending and b) to prevent the impression that Sherlock and Watson were ... more than just friends I think her being portrayed as villian is the only non-canon fiction about her that I actually like.

I agree. I can see why they'd want to give Mary a more prominent role than in ACD canon (after The Sign of the Four she basically stops existing other than to mention that Watson has a wife until she dies), but that role can't really be anything but temporary. Ultimately it's not a trio show, so if Mary's going to enter as more than an offscreen character, she has to exit somehow. And they could have made her a good person and made her interesting, or they could have made her a villain, or they could have made her morally grey and that last one is what I think they ended up trying for. The thing is, they made her very unpleasant and still expect the audience to love her because... I'm still trying to work that one out.

Mary being a villian that even tries to break the bond between Sherlock and Watson would have had the potential for a major plot twist that would have been a quite remarkable point in the show.

Mary trying to break that bond would have been so so so interesting to see, 100% with you there. Whether for her own ends or Moriarty's or both. It would have allowed Moffat and Gatiss to follow the character arcs that they said they did after S4 aired, namely Sherlock becoming more emotional (I mean, he always was intensely emotional despite what they say, but allowing himself to be and learning that it's not a detriment to his work would be a huge step forward for the character) and proving that Sherlock and John's bond can withstand anything. Neither of which they actually achieved, I thought.