Surefoot, I think it's a more than good enough system. It's true that it needs the block to be as big as the socket, but thats no bad at all. Many blocks are so huge only for being able to attach them using the AMD holes, not because the perform better being bigger. For example, in every test I've seen Maze 2 performs only marginally better, if any better at all, that Maze 1 (much smaller).
And about the danger of breaking the socket slugs, I think it's not a problem if the 3 slugs on each side are used. Keep in mind that a lot of heavy copper heatsinks use socket slugs, even only one on each side on most cases. And heatsinks, being much taller than a waterblock, apply a lot more of torque on the socket slugs. Any WB is short enough for not applying that kind of pressure on the socket.
In my opinion, using bolts, springs and nuts isn't neccesary in most circunstances, but hey, I'm not saying it's not a better mounting system...
Like you say here, just my 2 cents...