#2 The United States title picture could have one or two or more challengers

Rey Mysterio ideally should have a United States Championship defense at TLC and hopefully, it will be a ladder match. There isn't much time for a build per se, but that isn't required to have a great match.
From the look of things, Rey Mysterio has two potential challengers on his plate - Ricochet or Humberto Carrillo. While they could easily have a #1 contenders match next week, they should ideally have a Triple Threat match at TLC instead.
If Drew McIntyre were to be added to that mix, it would be perfect since his size brings an entirely different dynamic in a ring full of comparatively smaller wrestlers. Either way, a ladder match would be fireworks and WWE shouldn't pass up the opportunity and simply omit him from the card.
A multi-man match being set for TLC is the way to go and it has the potential to be the match of the night.