I've asked this question in each of the last couple years of Lotusphere/Connect at the BOF and in the Labs.
The answer always is they're aware of the problem and would like to do something about it.
Nothings been done yet of course. It's a big undertaking.
We made a big plea last year or the year before to suggest that the older Notes Client design elements are that big a problem - which I think is a big part of the problem - that they come out with some kind of "XPages Only" designer. So it gets rid of layout regions and all the other crap. Ideally Forms, Views, and just the XPages stuff. It all comes down to time and resources but it's now getting a little silly.
I THINK another key part of the problem is how close designer is tied to the notes client. They use the same threads and stuff I believe. Which was one of the main reasons why I think some kind of XPages only designer is our best hope. Last year the people in the room at least said that even if an Xpages only designer had less pure features to begin with. If it gave them a newer cleaner base to move forward with then we were all for that.
I'll certainly be asking it again. But sadly I'm not holding my breath for anything new.
Dave