I always took modern-day interpretation of ticket levels to be more about scale of ride rather than quality or popularity. For example, Rat is an e-ticket, but not very good (IMO, having ridden it), while Alice in Wonderland in DL is likely a c-ticket but one of my favorite rides in DL.Disney still uses “tickets” in its nomenclature. It’s always been subjective as it’s at least partially based on popularity. Some will argue Rat isn’t an E but that’s honestly silly. It’s a large-scale, heavily themed, marquis attraction for the park it will open in. That’s an E. Some attractions fall in letter over time when they stop being marquis attractions (i.e. they become less of a draw to guests; see Country Bear Jamboree).
I’ll be roasted but right now, Slinky Dog Dash would be an E. That is, if they still charged per ride, you’d pay the most for it. I suppose popularity trumps all other factors in the traditional ticketing strategy.
To prevent this from going off-topic, I’d be thrilled with a c-ticket Poppins dark ride. I think WS is well-suited for rides of this scale since the pavilions are already basically e-tickets in and of themselves.