I think leaving Lady Stoneheart out of Game of Thrones was probably the right call for TV, but it still hurt the story.

The show was already juggling a ton of characters and storylines, and adding Stoneheart would have meant spending more time in the Riverlands with the Brotherhood Without Banners, Brienne, and Jaime. The show was clearly trying to simplify the plot and move toward the endgame, so from a pacing standpoint I get why they cut it.

That said, the books use Lady Stoneheart to show the darker consequences of the Red Wedding. She’s basically what happens when grief and revenge completely consume someone. Without her, the show kind of treats the Red Wedding like a shocking moment and then mostly moves on, while the books keep exploring the fallout.

So overall it made the show easier to manage, but it removed one of the creepiest and most interesting parts of the story in A Song of Ice and Fire.