The one thing I've noticed about suppression values in-game is that (at least as far as I can tell) the shotgun has the worst of all ballistic weapons. I suppose this makes sense at long range where the blast has dispersed somewhat, but at close range, even when the shot misses (which is relatively common for the 20-TU option), the mere sound and power of a shotgun blast up-close should be more suppressive than a three-round burst from a rifle. Two consecutive near-misses from a shotgun at a range of four tiles just failed to suppress a Caesan non-combatant in the game I'm playing now, which is the reason I came over and posted. This just seems insane.
Just a suggestion- perhaps shotguns should receive added suppression value below a predefined range, say seven tiles or so?