I am not a bookie, but I have known a few living in Brooklyn for the first 30 years of my life. First of all, media darling popularity has little to do with opening odds. It might adjust the odds slightly, but it will not be enough to overcome the actual relative strengths of the teams. The easiest bet to set the vig for is a bet where there is an opposing bet. On a moneyline bet, Bookies would like equal play for the Ravens and the Patriots. The vig on such a bet is right in the open for the betters to see. The vig on futures bets is very difficult for the ordinary better to understand and see. It is also more difficult to set the odds to get the proper distribution needed for the bookie to get the desired profit. The better those odds are at predicting the actual betting distribution the better for the bookies. In a futures bets at the beginning of a season there is a lot of time to adjust the lines to reflect play.
In a shorter duration futures play like the odds at the beginning of the post season, there is much more pressure to be right to predict the actual play by the gamblers, because there isn't a lot of time to adjust the odds. They need to know if a team is hot, injured, etc., because the gamblers will certainly know.
Yes, the odds are adjusted to the amount of play, but in the end the relative rankings are as good a prediction of relative strength as you will find. Bookies might differ on close calls. One bookie might have team A as 10:1 and team B as 11:1. Another bookie might have those in reverse. You can argue the relative strengths of those teams, but there is no arguing about the relative strength of a 2:1 team vs. a 10:1 team. The odds as they are set today have the Angels and the Yanks as being much stronger than the Red Sox. I think that is probably accurate on paper. The Rangers and the Sox are pretty close, but I don't know if those odds have factored in Darvish.
The bookies are almost always right. Do their opening odds precisely predict the Champions or playoff teams? No, but at the end of the year, the teams that are predicted to suck usually do suck and the teams that are favored are usually pretty competitive. If anything, the fact that the Red Sox have such a broad fan base and popularity probably artificially affects the odds to lower them relative to other teams rather than to increase them. The Rangers do not have the same kind of following as do the Red Sox.