I know it doesn't constitute laziness, but when you look at a game as massive as Fallout 3 or Oblivion, with all the thousands upon thousands of lines of dialogue, you must admit that doing mocaps for each and every one of them would lengthen development time significantly. It's also very likely that many of the mocaps would be poor quality and just as hard to believe as none at all, and only doing mocaps for essential characters at essential times would give the impression of inconsistency. Though I do agree they could have made the ragdolls move a bit more.