You may want to vote for one or more of these feature suggestions:
A workaround is to select a Custom Interval on the Trends page, then select the Timeslice tab, then view the Resources section below the main Trends chart. You can change which Resources charts appear there, and in what order, although you are limited in how many you can select.
Ditto to what was mentioned. I like the resources view to see what I have at my disposal for potential correlation to the waits, but pretty much never work from that view. I work pretty much solely out of the trends view and then bring in appropriate resource metrics for correlating events with potential resource contention.