Bitches please.
Role-playing games are adventure games that let the player create his own character(s) so he can experience a more personal and unique adventure in a simulated world. That's the whole purpose of stats, classes, algnment systems and so on since the early days of D&D, to let players explore a setting on his own terms and forge his very own narrative.
But of course, if the game itself is mechanically weak and all these choices end up being cosmetic, they become pointless and there's no RPG. This is why a proper RPG has to constantly test a character's strengths and weaknesses, and by far the easiest way to do so in a consistent way is through combat. This is why most RPGs are combat-centric games (combat's not a defining aspect of RPGs, but it's stillvery important), and why turn-based combat is usually superior to real-time gameplay that would override some character attributes.
This is of course how our founding fathers coined the term Choices and Consequences, before retarded storyfags twisted its original meaning. Today when people talk about C&C they mean superfluous stuff like branching storylines and dialogue choices, but back then it was all about character customization options allowing unique playstyles, and a gameworld supporting them.
So, which games qualify as RPGs according to this classic definition?
- Wizardry: Plenty of customization options, plenty of deadly combat testing character builds and providing consequences, some little moral choices allowing even more player expression, highly randomized outcomes and perma-death making adventures even more unique to the player.
- Ultima: Weak customization options and combat, but allowing plenty of freedom in how to approach the world and game mechanics, so each player will master the game at his own pace and order, making each adventure unique. They have also quests with multiple solutions and some moral choices affecting how the adventure unfolds.
- Sword of the Samurai: Poor customization options, but plenty of ways to solve problems, moral choices with consequences, quests with multiple outcomes, and so on. The game allows the player to make his own character and forge his own adventure through its mechanics, so it's an RPG.
- Quest for Glory: Plenty of customization options allowing different playstyles, plenty of quests with multiple solutions testing character builds... Despite playing like a point and click adventure, this is a straight out RPG.
- Some JRPGs like Shin Megami Tenesei or Uncharted Waters: Full chargen, some customization options beyond just combat-related skills, and a world reacting accordingly.
- Planescape: Torment: Plenty of ways to make disctinct main characters, not only through stats and classes, but also through actions and dialogue options that let the player choose personality traits, that would later have consequences in how the experience develops.
- Expeditions: Conquistador
- Disco Elysium: I haven't played this game so I can't tell for sure. If the game's mechanically strong, with non-cosmetic customization options allowing unique playstyles, then it's an RPG. On the other hand, if character builds are cosmetic and consequences consist only in fluff text, then it's just an adventure game, or better yet, a non-game.
If the game doesn't care about character customization or letting the player forge his own adventure through game mechanics, then that's probably a tacticool game with stats, an adventure game with stats, or an action game with stats.
- Plenty of old-school JRPGs like Final Fantasy IV, VI and VII, Chrono Trigger, Earthbound, Dragon Quest IV, and so on, which are actually adventure games with random encounters and grinding.
- The Linear RPG
- Questron (it cloned the grinding parts of the early Ultimas, but it never allowed the player to make his own character or forge his own path, as it was deprived of everything that made the first 3 Ultimas good role-playing games).
- Plenty of modern action games that are just gamifying their systems with level ups.
There are many ambiguous cases though, these games don't care too much about what RPGs are about, but due to convention or heritage they kind of offer some options anyways.
- Dungeon Master
- Lands of Lore
- Diablo
- JRPGs like Dragon Quest III and Final Fantasy V that let you customize your party members, despite being too concerned with suppressing player expression in favor of their rigid tales.
- Dark Souls
- Fallout 4
- The Witcher 3
This is what moved this genre forward, if you don't like it you can always play squad tacticool titles and wargames.