I think its kinda of a combo of the 2 plus more.
Risk takes planning but the actual battles are a roll of the dice.In civ you have more military influence thru technology.You can research better quality units which will be decisive in battle.
The fact that you can win without ever firing a shot,or form alliances,or engage in peaceful trade and negotiations brings the simulation part into it.Although this is far from perfect as far as the AI is concerned.
And the fact that these 2 "sides" of the game go hand in hand along with other "sides" make a truly great game.Civ2 and MGE are the only games I have that have made it past 6 months of play.
not to mention the exploration side