There are two or three things at the base : the story/narrative, the mechanic itself (gameplay loop), and the choices. What you describe is the gameplay loop. To make it interesting, it must renew itself, so be varied enough and have some depth.

In a single player game, the renewal relies on the encounter design. The depth is the mechanic for the gameplay loop (in skyrim that would be the various weapons and spells first). MP games have less problems for renewal because players invent new tactics and play differently. But game balance and dlc are still used to renew the gameplay anyway.