With the AF and ISOs, I think it's hard to balk at the price. The 5D3 is a sweet machine that will allow for unmatched low-light photography. And as some have already noted - considering inflation it's actually less than the 5D2 was in 2008.
But, if you wanted to do straight comparisons - I don't think a jump to $3,500 from $2,700 over 4 years is enough to warrant pulling out the pitchforks. $800... that's $200/year, or a couple of portrait gigs.
Anyway - I voted that the price is justified. Considering I just sold my 5D2 for $2,000, having to come up with $1,500 for the latest and greatest technology in pro-photography is not too much to ask, at least in my opinion.
I've no doubt that you 'll enjoy 5D3 cause its a pretty solid offer.
Concerning the price, consider there's a competing product from another brand from the same country! And its not that upon launching it a week ago there was noise about it being 500$* cheaper despite the inflation!
Perhaps the fuss about the price is getting amplified cause all Canon's latest offerings were pinched up, some by a serious margin
*even more actually, i think d700 had higher MSRP than 5dII