The Angels posted the best record in the American League this year, but it doesn't mean they were the best team or are prohibitive favorites to win the pennant. They're neither an exceptional run-scoring nor run-prevention team, and their run differential was only good for sixth in the league this year.
They ran away IN a weak division, going 22-9 against Texas and Seattle, and won plenty of close games via a strong 1-2-3 punch in their bullpen. Their current roster is actually a little better constructed to win in October than it's been the past several years, which has to be music to Angels fans' ears given their quick exit last October.