What you need to remember about the Granny Smith parts was that they were made to be the framing device to Applejack's story. Remember, the point was that she'd forgotten what was really important about the reunion and didn't let the moments make themselves. They were made to create contrast to what Granny Smith had experienced with what Applejack herself was doing. The athletic and competitive Applejack focused more on the intensity of her events and going above and beyond rather than respecting the heritage of the Apples and remembering it as a reunion rather than a state fair-like production.
I think the Granny Smith segments were necessary to make the episode come together and to explain why what Applejack was doing wasn't going to work.
Also... would anyone have guessed that Cloudchaser, Bon Bon, or Hayseed Turnip Truck were members of the Apple Family? ^^;

Still, it adds a lot more depth to her character than what most "current-day cartoons" tend to do (keeping it all happy and stuff). Why did the depth of the 90s-2000s cartoons have to leave? 
