OK, since I started this as serve mainly as random discussion matter, I will try to answer as much as possible.
I'm not entirely sure what "wormhole abuse" exists right now. Wormholes are usually pretty heavily guarded by ...
I think people usually form main attack fleet other than some defensive fleet. It happens often that force which gather near worm hole guards are trivial if you make your force in and out frequently enough. Mere
handful of AI ships near hole will vanish in front of your main fleet in few blow. Non the less to say guard post fire power are almost negligible by its intention.
I do like the idea of an option where wormholes are located on the outer edge of a system...
If AI could identify human main force(fleet aka blob of ships) in some way, they could readily assemble ships near exit point for similar effect. There also could be placed some defensive structures notably the mine fields.
I don't know about this "ships are invisible on the outer rim" thing though, I don't really see how it make sense or how it would add in any way to the game.
Actually it doesn't have to. Worm holes by it self, they are not found in reality and people are just supposing they might exist.
This is game. Exploring game mechanism for greater fun is more constructive than just exclude the possibility
from the start with with some prejudice.
There could be degree in sensor/search level on player's human side.
At lowest level, player wont know anything about.
Next, player will know how many of them are present in his planet.
Next will be the number and types of units.
Higher sensor could also reveal the guessed position of enemy ships in form of dots.
Later they could show you exact place as dots. The ultimate sensor will reveal the entire planet.
I want to create a situation where outside of AI progress, there's secret retaliatory forces piling up hidden in fog of war. Space used to be big and dangerous but current game shows too much in my personal taste.