Event-driven program runs are tricky to add in the general firmware because the need for them is very customized. If you have programming skills, you can certainly modify the firmware to add such support. Another possibility is to make use of IFTTT — for example, have the ‘IF’ trigger be some kind of weather event (this depends on what type of weather events IFTTT supports, it may support wind but you will have to check), and define the action as a manual program run command to send to OpenSprinkler. A program can be set to ‘disabled’, that way it won’t run normally, but it can still be started manually using the /mp command.
About the number of programs, we are planning to add support to store programs in the on-board microSD card. Once this is done, the number of programs can be increased a lot.