as soon as 1D C MKII is announced ... which is probably never.... But wouldn't the brand new 1DX MkII (priced at $6K) have to affect the current price of the 1DC (originally $12K and now $8k)? Just dreaming that the 1DC could drop to $4K...
Seriously, 1D C will be phased out, so the discount depends on the available inventory. My guess on what will be the next $6,000-$8,000 pro level camera is "I don't know". Let's see what the NAB'16 brings.