In the grand scheme of things compared to loads of other cases that I have seen because of constraints like money, time and effort, skills, I really don't think there is anything personally left for me to do to my case, and I'd give mine a 6/10 too.
Computers used to more or less tend to run as fast overall as the slowest component (hence the term bottleneck). Not so much these days, but depending on how a system is bottlenecked it can determine if one specific thing is going to drag down the rest of the system. Regarding SATA standards...
I generally like all the B&W speakers. Some of the KEF stuff is really nice too. I personally want a set of the KEF Q700's for my mains (I only have a 2 channel setup personally [http://www.nrnl.org/post129.html#p129]). Using these you could then maybe have them matched to a REL T2 Subwoofer...
9/10. Epic looking build of the stacker. Please check mine out, give a vote and feel free to leave a comment here --> http://www.techpowerup.com/gallery/2827.html
6/10. I dislike the messy cabling and the random fan in the middle of nowhere. Thank god at least for your Corsair cooler. Case itself isn't too bad though, +1 for encouragement for painting and the epic score.
6/10. Looks excellent. Is it possible for you to route the mobo cable around the back? Also you may be able to shorten those pipes on your Corsair cooler.