That's a bit harsh.  And only partially true.  Each Halo game introduced tons of new features and aspects.  They sold because they were quality titles with endless hours of replay value and multiplayer.  CoD games are more fitting to what you described.  Mostly just new weapons and maps but the same game with not much added features.

like ragebot said, "noob friendly".

A Halo name on it.

Split screen multiplayer online, I mean 4 players should be able to play from one PS3 online. Halo's the only game I know that can do this with 4 players. It's one of the best features ever in any game.

I don't understand the people who had problems with the controls, I play all shooters on PS3 and 360, Kz2 is one of my favorite games, I don't see any problems with the controls. I think a good coop mode, would really do well.

its all about the adds shown on tv as well as the trailers shown on the internet.
that my friend will generate sales.
think of it like a movie, you'll probably already know what the storys about before you watch it (thanks to previews and trailers)
the main reason you watch it is for the story and nothing more.

Smoother controls
Party system/Matchmaking
Local multiplayer
Some sort of co-op mode
Better ad campaign

yeah but if you want it to sell really well you woud add the name "call of duty",  or "gran turismo" or "mario" lol funny but true.

Not having R3 releasing just a few months before it.