I can't explain why the requirement was put into 2008. But Bill Brooks explained at a seminar I attended that it was taken out of 2011 because it was mainly for lighting protection and lightning risk varies with location, so the CMP decided it should not be in the National Electric Code. Let the customer and/or local jurisdictions require it if they want, IOW.
If you live in an area that's prone to a fair amount of lighting, that should encourage you to include a grounding electrode at the array.
