Please correct me if I am wrong here but this is just what I thought after looking at it to buy.
1. I/O intake fan. Traditionally rear fans are exhausts. An intake on the I/O will pull in warm air rising from the GPU exhausts and send it to the CPU if it ever makes it, which brings me to #2.
2. Is the I/O fan really powerful enough to pull in air and push it against the flow of the air from the CPU fan? The CPU fan air will go down, hit the CPU and want to go left and right evenly. The air going left will push against the I/O fan and most likely be powerful enough to push through the airflow. If not, at least create a static "wall" of ever heating air next to the CPU.
3. The CPU air that goes right will hit a solid wall (the furthest left stick of RAM), working its way round will flow past the other 3, cooling only the edges if you are lucky.
4. The southbridge (let me be retro...), the air flowing down to the Z77 will already be heated and once past will flow out the right hand side of the motherboard and INTO the hard drives (or at least where they are commonly stored). Should you have an auxiliary intake on the inner side of the drive bays the situation is even worse. The hot air is then mixed with the cool intake, disrupting the flow and creating warm air. Which of all places, is then pumped into your GPU. (now re-read point 1)
Those are just a quick few off the top of my head. Please disprove me. I do really like this board and want to get it, but these design flaws are holding me back.
If anyone who has this board can disprove me by testing this out, PLEASE DO!