If they take away the starting it'll not only mess the film up but it'll also deprive people of a spectacular attack by a horde of mongol warriors. The start isn't absolutely needed but you could argue that about a lot of films. The american film industry needs to stop treaing their audiences as if they're all 14 year old kids with the attention span of a gant. It's also an insult to 14 year olds that they assume they can't cope with anything complicated
I'll be going to the cinema to see it in the Uk on the 5th of October anyway.