im not so sure that decreasing the max distance on the phasers would make the sphere of battle smaller - tho i could be very wrong...
not quite, if the ships are fast and agile.
but heavy ships like the galaxy or the warbird will come closer when they see their weapons barely damage the target.
also, you can make the ships fire torpedoes closer by making them get out of guidance or disappear closer
it won't make the AI come actually closer, but make them think deeper when they attack, not just "ready?->fire", but more "ready?->close enough?->coming?->weak?-fire"
(something I learned by waaaaaay too much testing ^_^) I
was going to pack some scripts for that, but, you know, Wowwy and CK left me on permanent hold lol