Depends a lot on what you expect from a villain. Darth Vader despite the iconic status of the OT is a rather inexpressive character for most of it. But when you insert him into the whole narrative of the series you realize this shrouded personality still remains mysterious and that details end up eluding the viewer.
For example, Vader seems to respect Peter Cushing's character over the entirety of the first film and largely treats him at his equal. As more knowledge about Vader comes afloat the viewer starts to realize that this goes unexplained and open to interpretation. This is not some sort of trait that is meant to suggest future progress of the character, be relevant to the plot nor anything ilke that, there seems to be something about how Vader functions that mostly escapes us.
In my opinion Kylo Ren is indirectly hurt by the focus in his character progression, given him too many traits that are plot relevant and very little depth as far as gratuitous things go. We get to see where Kylo fits exactly in each of these films, with too much hand holding, too little second hand information, too many emotions and personal development and too little of how he fits in the universe. This makes him less satisfying somehow for me, I even surprise myself caring more about Commander Hux as he is clearly flawed and petty, but he rises to the occasion at times and seemingly learns from the mistakes of others.
I think what I mean is... That both Hux and Moff Tarkin are better than these darkside villains wannabes uhuh