6_Qubed said:
I am tempted to say in all seriousness Saints Row the Third, due to the fact that it has a level-up system, upgradable skills and weapons, and customization options. You are playing a role in this game, even if that role is not a swords-and-sorcery one.
That's an interesting way of looking at it, but I'd still say it's not an RPG. Not because it's not Medevil (after all Fallout is an RPG with guns), but because there's no real story behind the streets of Steelport. Oh sure, there's the main story and there are tons of people, but there's no direct exposition related to them besides what the main story dictates. That leaves you just to play around in that world, which is fine, but then I'd still class it as a sandbox.
It's true, however, that the definition is based on pretty shaky grounds, considering how sandboxes and RPGs are different, but sandboxes and a lot of RPGs can at the same time be umbrellaed* under "open-world games".
*That's right, I used it as a verb.