Create a crowd-source mapping tool
The names of so many places change in the records, for any number of reasons. I would love to see a map that shows the boundaries of these regions, based on, for example, how a particular census defines them.
This idea is prompted in part by the work I've done with Lancashire, specifically great Manchester, and in particular the Rochdale area. One family might live in the same spot for 20 years, but the name of that place might be different across four consecutive census. For example, in the four censuses from 1851 - 1881, one family I've worked on live in Spotland, Rochdale, Whitworth, and then in Rochdale again. While there seems to be a defined relationship between these places, they often seem to be used interchangeable, or they change depending on population, etc.
Each of these census years would make up a layer of the map. Concurrently there could be a layer for the enumeration district (which in some ways might be more useful).