Two thoughts.
@ixu 's thinking is on track. You can’t add CTs without having commensurate sampling CPU and reporting bandwidth. Speaking from experience, the current Sense monitor is pretty much tapped out on processing power handling the mains, solar, plus incoming data from about 20 smartplugs (HS300 counts as more than 1 but a little less than 6). So you really need a new Sense box for every 4 CTs. And even then, you would probably want ealtime subtractions of noise to happen in a single Sense monitor. So I’m guessing that Sense would need to move to a new architecture if they wanted to do at-speed “noise cancellation”.
As for the “stacked area” and “stacked column” charts - I’m sure Sense will get around to adding more reporting graph options. I’m hoping that they add a degree of customizability and capability similar to Quicken or Mint for finance. In both of those you can do graphs on preset or customizable time periods, by selected/all categories and subcategories (a mixture of predefined plus user defined), and by custom tags…