Disregarding the TCW series, we didn’t get much in the prequels, and he was in Episode III for barely a few minutes before being de-handed and de-headed. If Sir Christopher Lee had not been cast, Dooku would be forgettable.
I don’t believe that you believe that Dooku and Snoke are equivelant.
Dooku is a character with a smaller role than Snoke, yet we learn more about him.
Dooku and Snoke are 100% comparable. And in 5 years you’ll probably be able to say the same thing about Snoke thanks to books and comics and TV shows - which is exactly how we know anything worthwhile about Dooku.
The thing is, that I wasn’t the biggest fan of Dooku either for exactly the same reasons. You introduce a disposable villain in one movie, and dispatch him in the next with little character development, as was the case for Darth Maul. It was a waste of a very talented actor to be honest, and his portrayal of Dooku contrasted starkly with his presence in LOTR at that time. However, I agree with MikeWW, that more context was provided for Dooku than for Snoke, which makes Snoke a more problematic character for me.