With regards point(s) deduction, the outcome would not be decided by the ref, it would be a panel who decides after the game.
Let's face it, most dives occur in or around the box in order to increase the chances of scoring. If the player dives, wins a penalty/free kick, then it's an unfair advantage as is disgusting. It needs to be a harsh punishment in order for it to have any effect.
The other alternative is if a goal is directly-conceded from a dive, ie penalty or freekick, then the goal could be disallowed retrospectively, which would therefore change the score. It happens with red cards: if a player is wrongly sent off, it is rescinded and likewise if a player fouls/hits etc another player off the ball and the ref didn't see it, they face a ban.
Why can the same not happen for an illegal goal?
A team wins 3-1 but has scored a penalty from a clear dive. Deduct the goal, which makes it 2-1. The points wouldn't change, but the goal difference would for both teams, which overall is fair and could still change the outcome of position in the table.