One I was thinking of this morning is adjusting defence based on speed. I was thinking about how powerful the YT1300 360 degree gun is, and I was picturing Han and Luke firing the turrets in the original film where they struggled to track TIE fighters flying across their bows. It was a feature in the Star Warriors game, but in X-Wing the ship is assumed to be entirely static at the end of each turn when the attack is made.
Possible House Rule:
Relative speed = Absolute value (i.e. treat -1, -2 etc. as +1, +2 etc.)
a) Attacker Speed + Defender Speed, if flying towards each other
b) Attacker Speed - Defender Speed, if tailing
c) Greater of Attacker Speed or Defender Speed, if defender is flying across the attacker
If Relative Speed = 0, +1 Attack Die
If Relative Speed >3, +1 Defence Die
If Relative Speed >6, +2 Defence Dice
This makes tailing an opponent even more lethal, it makes head-on runs extremely challenging, and it means smaller ships should fly as fast as they can straight across vessels with 360 degree guns relying on pure speed and good fortune.
Head-to-head: each ship is within the other ship's fire arc.
Tailing: rotate the defending ship 180 degrees. If the attacker is within the defender's firing arc, the defender is being tailed. Now rotate the defender back to the original facing. (marginal calls go in favour of the ship with highest Pilot skill)