I would love to be able to set date ranges to roll both in the custom date ranges and in segments.
The ability to make a custom date range roll would be great. Also it would be fantastic if rolling date ranges could be used in a calculated metrics so you could do things like difference between this week and last week etc
Rolling dates in segment would be very powerful when you are analysing user activation.
You would often want to see "Of those who bought product A a month ago, how many are still coming back today, and what else have they bought?"
You can now create custom rolling date ranges and use them within Analysis Workspace, and also use them within segments (which means you can then put these rolling date range segments in calculated metrics).