Without having any inside knowledge, I could point to a few reasons why I would call it impractical.
First, that was the seemingly the original point of this thread. From the staff responses it appears to me that this is not practical at this point.
Second, purely based on time and effort, more coding might not be possible for the dev team. This was also hinted at by staff in this discussion.
Third, per WildCowboy (post #24) the intended goal of the recent comments bar is to draw in visitors to the forums. You and I are both interested in using it as a curated list customized based on our login, but visitors have no log in and would therefore not see anything or would have to be given some type of designation for comments to be generated. Again, that would take some work, planning and ultimately time that may not be possible.
Again, I think it would be a cool idea, but i just don't see it being practical without a full site redesign. And for a full redesign to be justified, we are going to need more than a 20 people out of almost a million voicing their interest in this.
That is why I find it likely impractical and also why I put forward a possible compromise that would curate a list for people like us, but also leave the front page as it is for visitors.