I'd agree that Odyssey is an RPG. In fact, I think it's very, very close to Witcher 3 in terms of the combined formula.
I'm pretty sure the developers were heavily inspired by W3, seeing how successful it was.
There's certainly no less rags to riches in Odyssey - as you start out in basically your underpants (ok, linen cloth "clothes") - and you climb the gear ranks from there.
Also, you start out with almost no powers, and it's quite satisfying building your character - considering it's Assassin's Creed. You definitely can't master everything - at least not in the version I played. You had to pick one path to focus on, then supplement it from other paths. Much like most CRPGs I've played in recent years.
In terms of starting power, it's on par with the majority of modern CRPGs that I've played. You don't start out with a table knife fighting small rats, that's true - but that's rare these days.
I happen to think it's better in terms of loot, exploration and progression than Witcher 3 as well.
The story is quite good, though definitely not on that level.
Now, would Odyssey benefit from going old-school and making the beginning sections a true struggle before you find your footing?
Maybe, it's hard to say. But I don't think the standard audience is quite ready for that.
RDR2, though, would definitely be vastly improved by implementing meaningful CRPG mechanics, including proper dialogue choices and character building.
It would also tremendously improve by not integrating its introduction of gear and mechanics through the linear story structure, because you're heavily curtailed in terms of freeform exploration in a big part of the game.
It would be better if there was a single main story line - and most of the rest of the missions would be available throughout the game, and the order was completely loose.
Of course, that's where the challenge of telling a proper story comes in - but Witcher 3 certainly managed it for the most part.
If you want a better open world experience - you're better off playing the Online version.
As for other non-RPG franchises that I would like to see turn into RPGs?
Well, does the Alien franchise count? We've had a few shooters and an adventure game.
I want a proper Deus Ex/System Shockian Alien game - full of loot, progression, exploration and non-combat options.