Provide the option to use decennial census data, especially 2010 Census data.
Ken Schwencke commented
I'd add on to this and say it would be super useful to download census 2010 (or 2020!) slices for a defined area using CR's interface
This is a reasonable idea, although some more information about why its useful is welcome. Are you looking for block-level data? or just for the specific decennial figures for certain cases?
Would you want it just in table form? Or would you somehow want to see the profile pages also integrate decennial data?