This is a fine computer and the 3770 is a great CPU. However, I should tell you that this leans even further away from optimal performance in Dolphin by dropping to a third gen Intel processor (IPC drop of about 20% in some cases). Still a good computer, and it may work better for your other purposes in mind. It is a worse choice when it comes to all out Dolphin performance though. Your other points regarding quality of components, warranties, and not having to build it are probably all true and valid (I didn't check).
Your point about the Wii is also true. You can't play in HD on the Wii, which is primarily why people use Dolphin. Nothing wrong with your proposed machine, I'm just pointing out the differences.
Your point about the Wii is also true. You can't play in HD on the Wii, which is primarily why people use Dolphin. Nothing wrong with your proposed machine, I'm just pointing out the differences.