Yeah, I'm both amazed and disturbed by that. Even if it was DLC from previous games, you'd think there would be something that has it all at a reasonable price. Seeing all that DLC ensured that I will never buy this game.
You have to understand real simulation games before just judging a game like that. The game by itself is quite complete. If you are a specific fan of any of the various DLC routes or trains, then you buy them. If you aren't you don't lose out on anything. The actual community regularly buys the DLCs at full retail price, but last summer there was a 75% off sale on all of it, so everyone pretty much had a chance to get what they wanted.
It's a pure simulation game, so if you don't like trains, then you have no reason to buy it anyway.
Another idea I had was the spy/sniper being able to climb into the soldier's rocket launcher and be launched across the map, dealing more damage, but no splash.