There are other previous RPG games that have burst attacks like d20modern or Stargate SG-1. This last proposes narrow and wide burst using 3 shots as some of you said before.
-Narrow Burst (3 shots): -3 attack, +1 damage
-Wide Burst (3 shots): +1 attack
In my opinion and experience playing Stargate campaings and adapting to starfinder rules it would have more sense to use as follow:
-Narrow Burst (3 shots): -2 attack, +2 damage
-Wide Burst (3 shots): +2 attack
Wide word doesn't mean attacking on different "squares", it implies just moving your gun little to hit any part of the enemy's body, no matter which.
For this reason I don't know if in this subpart of automatic attack called "burst" would have sense or not to ban critical hit. On wide burst attack you are attacking whatever you can (here I understand there is no critical hit possible, or only by pure luck) but on narrow burst you are trying to focus on enemmy's movements (inside same square = Dex) meanwhile you balance weapon's recoil.
