V_K
Arcane
It's monotony. Even with the best combat design, if all you do is fight, and fight, and fight, it gets real tired real fast.so what's putting you off combat in one place in the game but not the other? It's certainly not difficulty.
In a good game, it's not just rewards that have to be considered, but costs as well.The more elements you put into non-combat approaches, such as stealth options, diplomatic options, bribing options and all the etc, the more you motivate the player to take the path of least resistance, especially if the rewards are equal (If the rewards are not equal then why would someone gimp themselves before the next, even harder fight).
By your logic, essentially, RPGs should be corridor shooters - because why bother with different approaches to problems when some of them will inevitably end up being better than others?