I'm not really sure what an RPG is. I do know what games are not RPGs.

In my opinion, a game cannot be considered an RPG without sufficient story elements. This includes various information and trivia that you learn from non-vital NPCs and "text items" as well as in-game descriptions of what certain items are/do and/or why/how they do the things they do. The characters need to grow and change over the course of the story. The story must clearly affect the character(s) and the character(s) must affect the story in at least some small way.

There's more, but I have to leave for now.