When the new structures come out, they will no longer have automated defenses. A character will have to shoot the POS guns. I know this is at least 3 months away, but it sounds like it would be fun for me to make. I just don't know if it would be big enough for you to sell? It would allow people to go on vacation without much worry of their structures getting destroyed while they are away.

High level overview of useful possibilities:
Monitor Eve API for EveMail/alerts about which POS is under attack. (Or just login for each vulnerability time.)
Login with character docked at the station under attack.
Assume control of structure defenses.
Change overview to display only attackers. (Think this is currently possible.)
Activate offensive modules.
Maybe stay logged in for remainder of vulnerability time.
Maybe support multiple accounts so more than 1 could be defended at the same time.