What is the problem?
Faction warfare is overrun by bots, this isn’t a joke, this is the game mechanic in which botting most severely disrupts the actual workings of a game mechanic.
So yeah what is causing this problem?
The fact that defensive plexing requires nothing but an actual ship, this ship has to do nothing but sit in a spot for 10-20 minutes and requires performing no actions at all. Bots do offensive plexing a lot less because that actually requires shooting a rat and doing this for the larger plexes requires an investment in ships that makes botting infeasible.
So what is the solution?
Make defensive plexing also require shooting a rat.
Leave the PLEX site empty until a militia member enters the zone.
When the happens spawn in a defender or attacker ship depending on the militia members faction. Same way this works for many missions where a ship spawn is triggered upon entering an area. Play a message (Caldari scum are attacking the site! or Enemy ships defending the site have arrived!). If 2 opposing ships enter just spawn both rats and have them do minimal damage to each other and prioritize shooting the player.
require shooting the rat to advance the timer.
This makes botting faction warfare overall harder, requiring fitting weapons to ships. The effect is larger for the larger sites. The novice sites can probably still be profitably botted, but small, medium, large would be a lot harder.
I don’t think defensive plexing in its current form is something many people would be sad to see go. The change is feasible in scope without requiring vastly overhauling other aspects of faction warfare.