The sprinkler controller I replaced with Open Sprinkler had one really nice feature I’d like to see in the mobile app. There was an up/down arrow button combo which would set the “percentage” of the program you wanted to run. At 100% it would use the program(s) as is. Setting it below 100% would reduce the duration of each station to water for that percentage of time. If you set the percentage low enough it would even drop a day rather than reducing the duration too much. Setting it to over 100% would increase the duration on each station.
This was a really simple way of reducing the watering in the winter and increasing it during especially hot spells in the summer. It goes along with the current feature of suppressing watering when rain is predicted, but gives more control rather than just on or off. In fact, you could connect this feature to the weather data and set the percentage based on average daily temp or something.
Anyway, I think it would be a really nice feature in the mobile app.