A large part of the appeal of Gundam was the fact that it marked a break from the traditional "Super Robot" genre of anime prevalent in the 1970s. Though there are still quite a few elements of that genre in the series (the Gundam was made by Amuro Ray's father, Tem; the White Base has on board three young kids as comic relief (though they do get redeemed in Zeta Gundam, where they are fleshed out); for the first half of the series, the three White Base mobile suits are the only ones in the Federation arsenal), the show broke the mold by portraying the mobile suits not as sentient, but rather as tools of war - though mobile suits piloted by legendary pilots such as Amuro or Char Anzable do tend to take a life of their own. In addition, the sides are not painted in black and white - it's made clear that the colonies do have quite a few legitimate grievances, and that the Federation isn't as noble as its PR department would like you to believe.
A large part of the reason many fans of the original series dislike the original opening is because it's a painfully stereotypical opening for a classic "Super Robot" show, when it was so much more than that.