I'll support this idea. I have a client wanting to track a bunch of specific pages like:

and so on.........

And there is no good way to do that in the platform.

This is a must have. There are no benefits to this restriction. :(

This goes hand in hand with needing more keyword availability.

Even rather than just adding blanket keywords, perhaps the ability to track the same keywords across difference devices(desktop/mobile) and across areas. For instance, I have several campaigns out of Denver Colorado, tracking both Denver and Colorado would be beneficial to see how we're doing in and outside the city as the local areas are within our service radius as well.

I'm looking for the same thing! We are running a e-commerce site with different product sets with different competitors, would be awesome!

Absolutely a must have or I have to look for another tool but I much prefer ahrefs!

agreed, this would allow the rank tracking tool to hone in on different competitors, since they are not the same for all categories.