I'm just spitballing here, as I have no direct knowledge of it in this particular case, but promo material from developers often show things that are a bit bigger on the eyecandy than you get at home, once you have the game yourself.
I think this is often due to the fact that the end user often simply doesn't have the computer power to run games with that much special effects content properly.
So perhaps these splashes were deliberatly tuned down for release to make the game run smoother for the average user, and the pictures could have been taken before it was tuned down.
Now, again, I don't know if that is the case here, but I know for a fact that lots of others games have promo material that can never be recreated on your computer at home.
I do know that I cannot remember having such splashes in V1.0 either.. These seem even bigger than the V.10 ones. Though I can be wrong.
Regards,
Fred