The Day one content is only a high-level rifle for people who pre-order, or a LMG for those who pay extra to get the collectors edition. Most hardcore gamers could unlock these within the first day or two of playing anyway if its as easy to level as CoD4, and casual gamers within a few weeks. Its not as big of an advantage as people make it out to be, since unlocked weapons are not always more powerfull then the starting weapons, sometimes they are just different, like in CoD4 the starter LMG had a much faster fire rate and better accuracy then the first unlocked LMG, but less dmg.
For many years games have been giving out special ingame stuff to people who pay for a collectors edition of a game. This is not something new.