The two things that the 6D is lacking that I think are important to a amateur/prosumer photographer are a second memory card slot and a pop-up flash. I just purchased a Nikon D600 for my father, rather than the 6D, because the D600 had the second memory card slot and a pop-up flash.
I could care less about WiFi and GPS....and video for that matter! I think Canon should have designed this camera geared toward purely still photography, and left out the video, which would have kept down the retail price and Canon might have been able to price it around $1,500. The Nikon D700 doesn't have video, and look at how many still love that camera!
I am fascinated as to why people feel a second card slot is worth a dime, I have had one for years and rarely use it, even then it is only for an Eye-Fi, something I could easily live without. Why do people value a second card slot so highly?
for example:
dual slots can be used as a raid setup so writing the same to both cards , that way you don't have to pull all your hair out of your head when a card goes corrupt 
or shoot jpg on one and raw on the other so on events you can ofload the jpg's quickly and keep the raws as backup
I disagree regarding card slots. Dual cards I'd say is more of a 'pro' feature. The average user is the type that will shoot in jpeg only, and consider 100 shots a huge amount, filling up a 16 gig card may take weeks. Also, the importance of files --- pro's need that redundancy, the casual user does not (yes they do want it, but no, it is not a NEED.). Now the pop-up flash I can see being useful and wanted for the casual user. that's my overall problem with the 6d --- it's kind of pro, but really not, and kind of casual, but really not.
I went on a fishing trip with my grandpa a few years ago and I took several hundred photos with my Nikon D700...the memory card I used was a Sandisk Extreme 8GB. I still don't know what happened, but when I went to download the photos, the memory card somehow got corrupt and all the photos were lost.
My Grandpa died last year, and I sure wish I had the photos from that fishing trip....if the Nikon D700 had a 2nd memory card slot, I would have those photos!
Now, do you get the picture of why I think a 2nd memory card slot is so important....you can't replace the moment of when a photo is taken! This has nothing to do with 'Pro' vs. amateur features!