To be really honest, I’d rather have paid 5-10€ for a complete DLC than getting a free but incomplete DLC. And yes, playing in a US map with US-style landscape and french street/town names somehow ruins the immersion. It’s not a major issue, but it’s something that could have been easily avoided.
Having said this, I still don’t regret having purchased Train Fever, and I’m eagerly waiting for future patches to solve these small issues. This is especially true with Urban Games as I know that they are listening to customer’s complaints and trying to improve things over time.