Me too. I loved the atmosphere of DMC1, and the badassery of DMC3. Combine those, and wham. The result would be quite pleasing. I agree though. DMC1 Dante was a perfect mix of cocky and subtle. He only jokes when it's appropriate. He was mature, and I liked that. You have to remember though, DMC3 takes place ten years before the first game. So of course there's going to be a sense of immaturity in his character. He went from not giving a damn to becoming a selfless and hardened individual. To me, that's character development. Also, seeing as how Dante was pretty young in DMC3, his behavior seemed more acceptable.
Now, about DMC4 Dante, I understand where you're coming from. I didn't quite get how he went from a mature man (DMC1) back to a childlike persona. One of the reasons why I loved Dante in the first and third games was because his character oozed variety. You see Dante angry, sad, frustrated, etc. In DMC4, we don't get any of that. DMC3 Dante has more in common with DMC1 than you think. Just Saiyan. Mind you, I actually did enjoy his one liners in DMC3. They were clever.