IMHO this really comes to the one question. Does this new or any other DLC implements something new to the game. So for example some work on more complex rail operations, signaling, some new features. Like this every route feels like seen before, because the feel of driving the train is basically the same. You just get the new scenery and new loco cab graphics. Which this game should focus on is expanding and improving the railway system and also driving experience in terms of physics but also in terms of authentic sounds. So again in my opinion focusing on core features of the simulator and expanding it and improving will benefit more in the long run than just making the route DLCs.