well, another thing I have done is add clip effects to manage certain things. For example, sometimes a particular vocal phoneme has a problem, such as "wh" being overly aspirated. I might split out syllable, and add a low pass filter just to tame that aspiration. This kind of adjustment of clips was very easily done in the old "layers" implementation. Rebuilding track layers was a part of that toolkit, and it allowed one in this type of case to easily see the clips all at once, and then perhaps to modify the crossfade. I have for example made the fade-out of the effected clip overlap more than just the fade-in of the following clip. That behavior is best enabled by expanding the layers or lanes, and without rebuilding or consolidating the clips may be far apart and need to be moved close to each other.
I'm not familiar with software development, but I would think that something like this wouldn't be terribly complicated to implement. It's not new functionality, really, just a sort of "macro", isn't it? As a former feature which was lost, it seems that at least the basic concepts of the programming for implementing rebuilding must be floating around at Cakewalk, right?