I don't care about the other preorder 'bonuses' but cutting out sidequests for DLC really bothers me. This, like Deus Ex HR last year, is a game where I just don't care and I'll buy it anyways but missing out on ANY part of the game because I didn't buy it at X retailer has stopped me from buying games new in the past and will in the future. Even if it's just a minor little thing, I like my games completely intact.
At least it'll be 50 cents on steam in a month or so, and either way the GMG preorder was over 20 bucks cheaper than what I'd be paying at EBgames after taxes and such. Even the season pass on the THQ site probably can't match up to that.