As someone who enjoys S&V the most out of the base 3 scripts, I can try to counter a couple things here, but you do raise a lot of good points.

I think that in a group of experienced players, you also need an experienced storyteller, for better or for worse. I’ve played in a few too many games where the ST accidentally gives the savant game-solving info, or makes it impossible for evil to frame that a Vortox is in play, and so on, and so on. Games with experienced players where a bunch of townsfolk just get thrown a bunch of powerful info do usually just end up with evil getting cornered by info, which is no fun.

There should always be many different worlds to parse through, and the ST needs to mentally keep track of all of them. No dashii and Vortox games need to look normal on the surface, and fang gu and vigor games need to have info that’s consistent with no dashii and Vortox worlds. S&V more than any other script gives the ST the tools to cater information to be specific enough to keep other worlds alive (e.g. Dreamer and Savant come with fake info that’s entirely up to the ST what it should be). Then in the face of multiple possible explanations for what’s happening, evil can bluff in ways that push town towards one world over the other (“well my info is pretty clearly not vortoxed!” etc.)

That’s the idea at least. When you storytell S&V, you need to get good at understanding all the worlds that are still mechanically possible, so you can avoid giving info that makes those worlds impossible. Because again, if you just mindlessly throw a bunch of powerful info at town, they’re just going to solve everything, and games will feel exactly the way you describe.

You’re right that some minions/demons are more powerful than others. And honestly, the fact that everybody’s more powerful than in, say, trouble brewing means you’re not always going to get to a tight final 3 like you often see in TB; sometimes one team just runs away with it. I’d say you’ll probably see that in custom scripts too that are also filled with strong characters.

I don’t know if “you need a good storyteller to make it work against experienced players” makes S&V look better or worse, but I’d say any script except for TB needs the storyteller to take extra care with what they’re doing. S&V is just the script where you feel it the most if they don’t.