Wrong. Character definition and progression defines an RPG... and you can't have either without stats/numbers.
"Define" - really? Since when did our
linguistic conventions dictate that all and only RPGs feature character definition and progression as a major feature?
People need to realise:
1) There's no settled definition of "RPG" - in the sense of a set of qualitative characteristics that (i) people look for and verify when they use the term "RPG", and (ii) that is common across most literal uses of "RPG". Different people will use the term slightly differently. This is an empirical claim which should be clearly true to anybody who has been around on these forums for a little while.
2) Is one usage of "RPG" correct? No. There are two reasons why you might think some usage deserves to be called the correct one. (a) Because it picks out the "real nature" of RPG-hood; (B) Because it facilitates communication.
2) (a) It's not the case that some usage of "RPG" picks out the
real nature of RPG-hood. There's no such real nature to RPGs. "RPG" is a genre classification driven by our interests. Whether a game counts as an RPG is highly sensitive to conversational context, depending upon the games being compared to, the purposes of the conversation, the salient features of the game, and so on.
2) (B) It's not the case that different usage makes communication difficult. Differences in usage only appear when less paradigm cases are under discussion. But communication isn't likely to fail even here. To the extent that we use "RPG" differently, we can put our claims in more neutral terms.
I do not see any good reason to say that there is some privileged usage of "RPG". One person says that story and immersion matter; another says that character definition and progression matter. Both are right - in their own idiolect. There's no need to disagree here. Accepted terminology for genre classifications just aren't that fine-grained. Better just to realise that different people will use the term slightly differently. To the extent that there is a substantive debate to be had (and often there isn't), we can resort to neutral terminology.