Yes we do plan to add more topics in the future. It’s difficult to accommodate everyone’s need, but given that the project is completely open-source, you can feel free to add your own topics as needed and customize it anyway you want.
“still” alive topic — isn’t this already supported? At least when I was using mosquitto_sub to monitor the subscribed topics, when the firmware is offline, it receives a opensprinkler/availability offline message.
water level can be added, that’s not a problem.
station started: this is already supported.