For contacts it would be nice to have an event for a change in state without having to specify the actual state.
My use case is that I have about 20 contact sensors for doors and windows. I use a rollup simulated contact sensor that reflects the overall system state. When all doors and windows are closed the simulated switch is closed, if not it is open.
Currently I have to define 20 event triggers for opening and another 20 for closing so that the state of the simulated contact sensor can be evaluated.
I can then use the state of the simulated contact sensor in multiple places without having to redo all the logic in each rule (although that is much easier now that rules can be copied).
Just a small improvement but would cut some of the rule coding in half.