I think it's likely that DPReview's web features may be complemented by Amazon's, for instance the option of giving grades to the review/reviewer.
I wouldn't be surprised if we'll see a one-click-purchase button for Amazon.com, too.
And I agree that there is no reason to even suspect that the consistency and depth of the reviews will change; Amazon.com doesn't appear to be in bed with any particular vendor, and stands the most to gain from reviewer independence.