More ideas for the talisman:
-Give it a maintenance penalty because of all the priests needed to attend to it... you might think twice about building a fleet of Talisman ships if they cost 4x as much to maintain!
-Give it the armor abiltity and something like 1 HP: the slightest scratch to the ship's hull will "defile" it
-Double the tonnage (and structure too, I guess)... 100kT is a lot of space to use for a single component, even on a baseship!
-Increase cost to somewhere along the lines of a Master Computer (which are overpriced anyway
)
-Dunno if this will work, but how about negative systemwide ship training - unless you have Psychic Ship Training Facilities, your ships will gradually get worse and worse at defense! (I wonder if experience can go negative...
)
-Allow the talisman to only be mounted on bases
-Not all of these at once or it will be useless!