Just a thought, but a possible UI simplification might be to combine AD and root depth into a single setting. Internally I think Rachio just multiplies these together anyway. You can see this by doubling you root depth and halving your AD or vice versa: there should be no effect on your schedule. For example, 12" root depth and 25% AD is equivalent to 6" root depth and 50% AD.
The single setting might be “maintain moisture to depth”. A UI preference could split these apart again, but having fewer numbers to think about might be easier for most who might want to venture into the Advanced settings.
What do you think? Is it more intuitive to set the two numbers or just have one?