The Warriors are a team that needs to score 120+ almost every night to get a win.
Notice how they are 0-5 against the Rockets, Spurs, Grizzlies and Cavaliers (I think they are.. correct me if I'm wrong).
4 of their six losses have come when they haven't scored more than 115 (and the other two were games that went to OT).
Maybe on paper they should stroll through the West fairly easily.. but teams with bigs can give them a hard time, especially late in the season with fatigue/injuries possibly kicking in (their bench depth isn't great either). Also, the Spurs and Rockets are within two games of the Warriors for #1 in the West, so while they have the best record in the NBA, it's not like they are running away with the conference.
Cavaliers are still the most complete team in the NBA IMO, but Spurs and Rockets (if Harden stays healthy and keeps it up) could have a chance to beat them in the playoffs. Rockets are likely targeting a big to help them as well (if they get Millsap, watch out).