I think that the Class 373, Eurostar would be a great addition to TSW5, considering the fact that it could open a new route from the UK to France, or Belgium. I would really appreciate if this train would be added.
Firstly there is licensing which Eurostar don't like to give and then secondly would you be happy to play a 2-3 hour route with not a good save game feature
Also, HS1 is already in game as far as Ashford. Its extremely unlikely they will recreate that and continue to France.