Not really. Going forward, all legacy routes (that is, Preserved Collection and TSW2 routes) will be sold as unified "TSW Compatible" DLC, as single items for one price; your rig will download the TSW2 or TSW3 version as appropriate.
Steam have got TSW base game for £14.99 at the moment but DTG have said that TSW2 will cease to be sold once TSW3 is released so you may need to get it tonight. This will the allow you to download the TSW base routes if you then decide to buy TSW3.
With such a leap in feature sets and visual quality, at some point it might be a good idea to permanently discount at least some "TSW Compatible" DLC in much the same way as the "TS Classics" collection. Some of the addons are getting up in their age and their quality for the price is questionable. Consider the value of Nahverkehr Dresden vs. Rhein-Ruhr Osten being marketed under the same umbrella and price. Of course it's ultimately up to what DTG's number people predict will generate the most profit. Cheers
I anticipate that happening over time, but probably not until some TSW3-native DLC has been rolled out.
