I honestly feel like he had wasted potential and could have been an interesting character to explore.
I mean, his original concept of an ancient force-user who saw the rise and fall of many empires is really intriguing and could have made him a very complex villain if it was explored more properly, instead of killing him in episode VIII and retconning him to be a humanoid strandcast.
I actually had an idea to make him more unique: what if he was an ancient force-entity (like the Bendu and the Mortis gods) that is able to use both the light and the dark side and wants to rule the galaxy because he has a different vision of true balance of the Force: by being able to control both sides and use the Force to its full potential? He could had his own opinions on the prophecy of the Chosen One, believing it to be misinterpreted and wants to take Ben Solo as his apprentice because he's the most similar to Anakin in terms of potential in the Force, being the perfect key to his plans.
And with this version of Snoke, the theme of the trilogy could have been about the Force being "neutral": it is not good or bad, but people can use it for kindness or sellfishness, depending on their intentions.
But this is just an idea that i had. What are your thoughts on him?