Actually, hamada, I think that guy made a really nice point about just buying the 5DII. A used II is already quite cheap and I don't think it will go down all that much more if/when a 5D4 were announced. That way, you can enjoy the FF experience for a few more years and then SELL IT when a new one is announced and you won't lose too much money. I'm not sure why you think a used 5DII will be similar money to a new 5D4 but that is just not true.
i only wanted to make clear my post is not about image quality concerns... just "purchase value".
i think i will go for the 6D and keep my 7D.
the other option would be to sell the 7D and go for a 5D MK3.
but i think i am more flexible when i keep the 7D.