Here we go again.
1. The design is one year old.
2. No normal desktop card can support a 4K display for anything but 2D applications. There's a lovely Anandtech article on the SLI Titans you need to keep 30-40 FPS at 4K.
3. 4K displays are *expensive*. Very few will buy a $4,000 iMac.
But hey, troll away!