The Shield 45 can be carried in all but the smallest "European" style pants pockets, using a suitable holster. I have a Springfield XDs, which I carry in that fashion. There's no need to downsize to .380 ACP or less, nor choose a revolver unless you prefer it.

A jacket pocket is not very practical. Any handgun is heavy enough to make the jacket sag, and it will swing around unless the jacket is very tight to your body. It slaps around even in a heavy winter overcoat. What do you do if you have to take the jacket off?

Shooting from inside a pocket sounds like a cheap detective novel, not the real world. If you put your hand on the grip you can draw very quickly, without tipping your hand if it's a false alarm.