Since we know that people have been able to 'unlock' the Dynamic Lines livery for stock included with Great Western Express, I'm sure I'm not the only one who would quite like for it to become an official add-on on all platforms. I don't imagine it would be a huge task, and I know GWR are generally quite happy to support things like this, particularly if it could help their charity partner in some way.
As a stand alone add on I wouldn't want it, PC already has it for free, and I can't imagine a ton of people wanting to fork the money over for a livery that's already been ages ago. But I agree seeing it officially released would be great, ideally as a free update. However if they won't do that then maybe including it as a bonus with something else would be great. Maybe with some addon loco for GWR, or maybe if a extension or new GWR route is made it could be included with that.
I don't think that First Group will allow the Dynamic Lines livery to be added under the current licensing arrangement due to it being a old livery which no longer represents the GWR franchise. A new arrangement would likely be required first and is probably very complicated and difficult to acquire.
If you're talking about some of the routes from Just Trains on TS1 (that are now on Steam), some of those routes require the old European Assets Pack in order to run it. And that asset pack does have the old FGW liveries included (both on the 43 and the 166, which were from the old GWML route iirc).
DTG has already said that this will not be coming due to licencing conditions, for the reasons elarthur has already explained.
