Honestly FO:NV is the best game Bethesda had a hand in but even then it was really just Obsidian. And honestly I would rather have Bethesda’s FO3 than a really faithful FO3. The Fallout IP before NV is really boring and the opposite of a game I want to Play IMHO
Personally, I wasn't that taken with New Vegas. It was a little too much saving and reloading, and it felt a bit more like D&D with guns to me than a Fallout game. I'll give them props for putting much more role-playing in it than FO3, and I can easily see why so many people love it. Closer to Fallout 1 and 2 than any of the other Bethesda titles, definitely.
The main thing here is that Bethesda games have never really been "bad". Buggy, clunky, half-baked in places, missing golden opportunities to shine, a little flat and perhaps even lazy in places, and they didn't age well...but absolutely engrossing experiences that I've sunk thousands of hours into over the decades, from Arena all the way to (the latest iteration of) Skyrim. Back when Morrowind was released, what it accomplished was utterly mind-blowing. I must have played Morrowind for about 5-6 years straight. Even when Oblivion was released, Morrowind never left my hard drive.
The biggest failing of Bethesda: they stopped getting
better. They kept using the same tools to build the same structures over and over an over again, all while adding a few new gimmicks to freshen it up. Now, like anything, I think gamers are tired of it. It's not "bad" -- but it's grown
bland.
Conversely, CDPR's titles have all been extremely unique. The experience offered in TW1, 2, and 3 are totally different gameplay experiences between themselves. I expect the same will be true of CP2077. I think that's why CDPR climbed on top and is managing to hold its place. Like I've said in the past, I'll probably never play The Wicther games as much as I've played Beth titles, or games like XCOM in the past, but I love CDPR's titles more.
So, just to bring this squarely back on topic, I'd say IP that would work best with CDPR's approach are ones that have extremely strong narratives and could benefit from more robust gameplay or design. (I still think a re-imagining of older classics like The Magic Candle or the Ultima series would be really cool.)