A strong suggestion for the WCML south would be the 221 as it would offer a unique experience other than the EMUs used on the WCML. I am aware that the WCML is modern day so these trains would have been replaced with the Evero’s in real life but I am sure adding it in game wouldn’t create too much issues
I think given the time period it would be feasible to have a transition timetable - i.e. 390s, 221s, and everos - would be great for loco variety. But I don't see this happening currently with the core issues causing such bad performance.
The clas 221 would be a great addition to tsw5 but the thing is that there aren't seen very often in the wcml South route