First, I generally agree about staying away from CD, although I had a friend who loved the CD in his truck (I believe it was a 6 cylinder Dodge). He said it really boosted his highway mileage, and he often drove from Virginia to Wyoming, in addition to lots of local country road trips.
Regarding "masking" the problem, I'm not enough of a gear-head to agree or disagree. But how do you "mask" such a thing? The rocker arm either stays on or it doesn't...there's no turning up the stereo and singing loudly when it falls off.
What problem might still exists? I'm sure we would all like to see a physical attachment point for the rocker arm, but if Mazda has arrived at the proper oil pressure to keep it attached under "all" circumstances. I guess time will tell. Perhaps there still are rare conditions under which it might fall away. I don't know.
I don't know. All I know is pretty much every auto company has had trouble implementing CD. Then you add to the fact that the 2.5 is one of the few(maybe only) 4 cylinder engines in the world with it. And it only gets you 1 MPG in FWD and 0 MPG gain in AWD. What's the point of it? Just put out a damn hybrid like everyone else.