The jump drive is already a module like this though. Im curious if there are thoughts towards an early game module that does much the same but with a larger detriment in other areas. Otherwise an empire with a single point of entry can completely stop any attempt at raiding their inner systems during a war early game.
First off, the FTL Inhibitor
itself is a technology. So your chance to have it early game might not be that good.
Secondly, if you need to close off a chokepoint that usually means that you can not expand into that direction anymore. Any systems on the far side of the chocke might be vulnerable to attack/raiding, because they are on the wrong side of that wonderfull fortress. So having that chokepoint is already a tradeoff.
Third, you can close off up to 3 at start.
Fourth, the number of inroads into your empire might not work out as well as you planned. Actually securing all paths into "your" section of the galaxy propably needs a lot of influence on early expansion into far-off systems. Indeed the more planets you can expand too, the more chokepoints there are and the more expensive it is to secure them all.
You might have the best defensive position, but latest when you attack you will have to risk your fleets against the enemy defenses. And if you take enough losses, that in itself will make you open for a counter attack.