I have a problem with your “great game” hypothesis. I think it’s necessary but not sufficient. And even the “necessary” part I think applies only to having a “good” game as opposed to a “great” or “admirable” game. Because the sufficiency part does involve having something new in the system.
I think the existence of a great game only proves you are a great author. And a great author could probably write a great game in pretty much any system going. That’s unless it is really poor indeed.
So a great game is more of a reflection of the author than the system, in my view.
Having said that, the existence of a great, good or any game, does mean a system functions enough to build it. And that’s well worth demonstrating nevertheless. Which is why i think it’s necessary.
On the subject of IF and “real” programming languages, Ren’Py is a massive counter example to your claim. It has a huge following. But despite that, i do agree that there are problems with this route. I see systems where people are basically chucking in either various derivatives of JavaScript, Lua, Python or whatever fancy language they happen to like a lot.
For me, I still like the DSL approach to IF, and it isn’t because i have a problem with “real” programming languages, it’s because I want the right tool for the job. Or, at least, a tool designed for the job as opposed to a general purpose.
It’s my view that modern systems need expedience as opposed to features. A good game is necessary, but, “How hard was it to write that game?” That’s the question I want to ask.
I want building a good game to be easy, not just possible.