All this post-necro discussion and barely a mention of SYSTEMS.
Systems > exploration = combat > everything else.
RPG is defined by its roleplaying system. If the system is shit, RPG is shit. If the system is barebones, is it even an RPG?
Frankly, a good system is good to play even in abstraction. If you've never theorycrafted, are you even an PRG player?
Exploration comes second. Sure, there are some superbly-furnished straight corridors of a game you can play through, but that limits replayability and excitement.
Also, adding unexciting short appendices doesn't count either.
For me, that's another definitive quality of a good RPG - being able to explore around, stick your nose into every nook and cranny, being able to take an ultimately rewarding detour and forget about the main "epic quest" for a while.
Basically, what's more fun?
Combat is also important, because frankly that's what the systems are there for.
Boring or obtuse combat will make the game a slog to play through, excellent combat will make the other lackluster elements more tolerable.
Frankly, an excellent variable combat is an exploration in its own form. If you can approach the same encounter in very different ways, it's super rewarding in terms of fun. Even if the game itself is a proverbial linear progression of 10x10 rooms.
But combat in an PRG can't be good if the systems are shit.
Setting, story? The dressing, the spices. You don't eat the dressing over the "meat and veggies" (which got theor wn flavour in the first place) unless you've got
shit taste.
Setting don't matter. Blaster or a wand of magic missiles? Plate armor or hard shields? What's the fucking difference?
Story don't matter. Fate of the world? Fate of the village? Nature of a man? Cool story, bro.
How does the game play?
A good story or setting makes an already good RPG better. It doesn't make a bad RPG good, at best it makes it tolerable.