The campaign was a ****ing mess! It was a pile of glitchy uninspired, boring, and badly-designed shit with piss-poor level design that tried not to be linear and as an effect it just made the linearity obvious, it has 1-dimensional enemy AI, and worst of all, the campaign was obviously an afterthought. The entire game was an excuse to put the multiplayer in a stand-alone game.
In CoD4, I was ENGAGED int he story. From the opening level on the ship at sea to the massive finale, I felt a ginuine emotional attatchment to the character's plight and the conflict the world was in. In WaW, I ignored the story completely, but that was on accident: I tried to pay attention, but the bad sound design and obvious writing/staging flaws kept preventing me from actually wanting to stay put, and the story itself attempted to be hard-hitting and emotional, but tried too hard. I didn't ****ing care when the captain or whoever got killed at the beginning of the game, the only thing I was thinking at that point was why the developers saw fit to allow the player to shoot the Jap that came out to kill him but not actually have him die until the story allowed you to. In CoD4, when a character dies halfway through the campaign, it's actually possible to save him and you get an achievement for it. But on WaW, there's no way to save him. I ****ing blasted him in the head at point blank range, and he still didn't even react.
Oh, and WaW is a side-game in the franchise.This is not based on whether the game actually has a number, but on whther the game engine is changed. It is like GTA: GTA 1, 2, and 3 were all games that had a drastic change from the previous one, but GTA Vice City and San Andreas were just minor updates to GTA 3 with new story lines, weapons, and vehicles. They were part of the series of games in the GTA 3 line.
Likewise, both CoD:WaW and CoD:MW2 are just updates of CoD4 with new stories and such.
This has more to do with programming than just the story of a game. For example, Mozilla Firefox 2.0 was released, and when 2.1 was released, it was a new product, but still just an update of the previous one. It's not untill they actually get into the guts of the program and change the basic ways in which it works that they actually call it a completely new beast, Firefox 3.0. One could argue that they didn't do this for Cod 2 and 3, because they were pretty similar to the previous installment, but then I simply have to say that they just started this trend with CoD 4.
You are obviously not talking about the same game I am.