Variety of Interconnected Game Systems and Activities  – A good RPG is effectively several games in one. The player may participate in several activities – combat (usually lots of combat), conversations, puzzle-solving, trading, crafting, breeding Chocobos, whatever. This would be bad enough, as the developer creates several games in one, but the various systems interact with each other in subtle yet powerful ways. Or at least they’d better, or they are stupid make-work activities.  For example, being able to do more effective trading or crafting will impact combat, as you will soon be entering the battlefield with superior equipment.  Being able to thrive in combat may in return improve your trading, as you can take down opponents with better loot. That’s a positive feedback loop that could go out of control – which is why you often find merchants in “lower level areas” with only very limited gear to offer for sale.

Balancing these different systems – effectively different games (even if not very good ones by themselves) – so they all make a complete whole can be a daunting task, and many mainstream games do a horrible job of it. But others have done an excellent job of it, and it shows. But the bottom line is that it’s a lot of extra work, even if done poorly.​