It's kind of annoying. When I'm following an NPC, for example right at the start of the game where you follow Hadvar or Ralof to Riverwood. When they're running, if you run with them then you overtake because they run slower, so you have to keep stopping to let them catch up. But then, when they're walking and you try to walk with them, they walk faster so you fall behind and have to keep running in bursts to keep up. It doesn't make much sense and makes it hard to roleplay.