This is a fairly simple suggestion, but something I think would be quite popular in Train Sim World 2, since DTG's previous British Rail-era routes aren't too bad. I am of course referring to Northern Transpennine and Tees Valley Line. I can't comment on West Cornwall Local as that's still not out yet. (4-REP and Class 33/1 image sources ~ Flickr) What I'd like to see is DTG or Rivet or whoever else make a Southampton to Weymouth and Lymington route, but have it take place in the 1970s. This is because, back then, the passenger services on this route were run with a unique mix of Class 432 '4-REP' electric units and Class 33/1 diesel locomotives hauling unpowered sets of four coaches each; the Class 438 or '4-TC'. The EMU would be uncoupled at Bournemouth, and the 33 would haul the 4-TC sets to Weymouth. For the return trip to London, the 4-TC sets would be propelled by the Class 33 as far as Bournemouth, where the 4-REP electric multiple unit would be waiting to take over for the rest of the trip to London Waterloo. This unique operating practice ran from 1966 to around 1988, as the South Western Mainline was initially electrified only as far as Bournemouth. It wasn't until 1988 when Weymouth finally got electric trains, in the form of the Class 442 '5-WES' units. These trains would initially serve with Network Southeast, followed by South West Trains, Gatwick Express and South Western Railway. This would also be a good opportunity to add the Weymouth Quay Tramway, as that would add a very unique set of operations to TSW, and probably make for a good selling point as well. Of course, the included motive power with this route would have to be as follows (amongst other freight locomotives and rolling stock that haven't come to mind yet): Class 33/0 and 33/1 diesel locomotives Class 421 '4-CIG' electric multiple unit Class 423 '4-VEP' EMU Class 432 '4-REP' EMU Class 438 '4-TC' unpowered coaches/driving trailers (The Class 150/2 from West Cornwall Local could also be added in as an extra layer, as this would depict the Heart of Wessex line services from Weymouth to Bristol (or at least part of the route).
I would dig this, could also add more to other Southern Region routes back then, if they make some of those.
33/1 will be made from the base model WSR Class 33 Green. The thing with Class 33/1 is that the MU system makes it compatible with SR EMU System used by 442 4 REP CIP but not the base model Class 33 Green TVL Class 37 DLC Class 20 & 31 Huddersfield Line the NTP Class 45 DLC Class 40 due to those being blue star Mu.