I always thought that the settlements were really empty and ghostlike, so I've been using player.placeatme command to spawn generic Nord and Wood Elf citizens.

Trouble is, they just stand around like cabbage people, apart from if I place 'em near an intractable object like a chair or a stall or something.

You guys should try it, it really adds a lot of immersion when you have hunters selling their furs and peddlers offloading their goods in Whiterun, however it's not very immersive when you kill them, guards don't seem to mind if you slaughter them one by one..

Warning: The placeatme command causes save game bloat.