I played all through year one on a Xbox 360. When TTK came out, I upgraded to the PS4 and got the legendary edition (included all the previous DLCs). I started from scratch. I actually really enjoyed starting from scratch and playing through the entire game and DLC's in order. Just now digging into TTK story. I would for sure go the route of starting over with a new character. Tons of new quests and things to do through the process. Enjoy!