Telika: RPGs are indeed being defined through many independant elements (progression, open-ness, character choices, story decisions, etc), and each game offers a different mix of them. Individual players decide not only what is the most fun, but also, independantly, what defines better their own vision of "rpg on a computer".
With that said, I play and appreciate RPGs more now than before. They more often match my own idea of what makes a game an RPG, and what makes it fun. In oldie terms, modern RPGs are more similar to Ultima than to Dungeon Master, and I appreciate this.
My vision of RPGs was always based around the idea of free-roaming in an open world, with an invented character, and having stories there. So, that defines stuff like Ultima, Fallout (both 2d and 3d), Arcanum, Elder Scrolls, Bloodlines, etc... It mostly pushes away to the edge of "my" definition stuff like :
- Dungeon Crawlers, which story and universe is just "you are in a labyrinth, solve the labyrinth". I had adored Eye of the Beholder, but I haven't felt I was roleplaying in it. And I kinda lost interest for the excellent Temple of Elemental Evil when it started being about the temple of elemental evil (as opposed to the surface adventures with towns and villages and stuff).
- Hack and slash aRPGS, that are focused on combat at the expense of story, which is also the case of dungeon crawlers by the way. I do not consider Diablo an RPG. But worse (and more unfairly), this aspect also disappointed me in Baldur's Gate, as I felt I was spending more time cleaning up maps than following the story. I enjoyed Neverwinter Nights a lot, but because I expected a Diablo-like. Many of these games are immense fun, but when I'm in a RPG mood I tend to stay away of that genre (which of course is not a genre, but more of a gameplay focus).
- Games with too strongly pre-defined characters, the more pre-defined the closer to an "adventure game" in my eyes. I do love adventure games, but again, it's something else than what I expect from a RPG. Still, this is my weaker parameter as many pre-defined characters can be played very different ways, and incarnate very different personalities and traits. It still nagged me, in Planescape Torment, to play out a pre-written character story, as opposed to parachuting my own invented character in an open universe. Super unexpected plot twists such as "you were the one reincarnation/amnesiac celebrity expected by the prophecy" do also harm this aspect, as, well, it prevents me to create another character than "the one reincarnation/amnesiac celebrity expected by the prophecy".
It doesn't mean that these elements make a non-RPG, but they make a game (dramatically or slightly) "less of an RPG" to me. Also, note the odd thing : stats and progression does not play a role for me. I could enjoy a RPG where a non-evolving character just roams through a virtual world, dealing with multiple stories in different ways (heck, maybe even without combat). Many would call it a very very open very very branching adventure game, but it would match my core RPG expectation : live, in a different world, a completely invented life with a completely customized character making his own customized choices through his own customized behaviour.
So this as background to explain why very few of the old tile-based dungeon crawlers (or their tile-based labyrinthic pseudo-surface sequels, where forests and towns could just as well be underground mazes to solve) appealed to me. Ultima and Wastelands are perfect. I had a strong roleplaying vibe from Faery Tales Adventures because of the freeroaming (despite limited story elements and limited character choice). I was considering Hero Quest/Quest for Glory as a great RPG(-adventure hybrid), despite its limited (yet sufficient) freedom of approaches. But I was seeing little difference between Dungeon Master and Shadowgate, because stats were not the relevant factor to me.
So, that's it for my own lack of "classic crpg" playing. As technology advances, subplot-driven open worlds get easier to implement, and RPGs more often offer me the Ultima approach that I couldn't find in Bloodwytch, Dark Crypt or Bard's Tale...
Personally, I take a different approach to how I define an RPG: I define it based on the way combat and other challenges are resolved.
In an action game, challenges are generally resolved in terms of collisions. If Mario's fireball collides with an enemy, that enemy gets burnt. If an enemy collides with Mario, Mario gets hurt; there is no random or stat based chance of dodging the attack.
In an adventure game, challenges are generally resolved deterministically based on the player's actions. Try to climb a tree and the you climb it (provided the tree is climbable and you have the right equipment). Fight a dragon with your bare hands; one dead dragon, slain by your bare hands. (Can you catch what I am referring to here?) Gap in the way? Jumping is deterministic; either you can jump over it or you can't (or you need a specific item).
In an RPG, challenges are generally resolved based on character stats and dice rolls. Attacking an enemy? Time to roll dice, both to see whether the attack hits and how much damage it does. Enemy casts a sleep spell? Oh dear, you got unlucky and are now asleep. (38 rounds later) enemy just hit you for 1 damage, you're dead. For an alternative explanation, in this sort of game, you tell your characters what to do, and then watch as your characters perform the actions.
Note that some games that are commonly labeled as RPGs are really action games by my definition: the Ys games being a prominent example. Also, some RPGs (like much of the Ultima series) have what are properly termed adventure game elements.