What did you mean by this exactly?
That he didn't know about the event windows (or space-bar)

A. Maybe have the Flagship capital ship have the ability to instantly cast back to home planet to help defend?
Someone has been playing too much War3!
B. Special weapon on home planet that can send enemy ships that are attacking back to the star unless this weapon is knock out before it is cast.
Um, wierd. That said, what planets (even home planets) need isn't so much more tactical slots, as better structures to put in them, primarily in the form of different function structures suck as flak cannons, "close in" cannons with heavier firepower, shorter fire times, and less range than gauss cannons, and some kind of "orbital shield generator" to protect other structures with (maybe make the planetary shield generator boost the shields of anything within the build radius?). As things stand, however, you can
really hurt any enemy that doesn't bring proper anti-fighter defenses by placing two repair stations, lots of hangars, and a phase disrupter all in a nice tight clump, ringed by gauss cannons. Add in a shield-generator to deal with human players that go straight for the planet with siege frigates and you still have a nasty defense problem.
I need to remember to cross-post some of that in the planetary defense thread (there are a few floating around), where you
too can give ideas on how to better set up defenses!