On the recently announced road map, we can see that the class 313 is 'in planning' for East Coastway on TSW2. As the only traffic on the Bakerloo line at launch will be the 1972 stock, I think that the class 313 add-on should include a Southern livery to use on East Coastway, and also a Silverlink Metro livery to use on the Bakerloo line as class 313s were used on overground section of the Bakerloo line, between Watford Junction and Euston. They were taken out of service in 2007. The livery looks like the below image:
Lets hope they add the full Watford DC Line, shouldn't be that hard, only a few stations. they also need to add ai 378s, 390s, 377s, 350s etc beside the line. Nice suggestion!!
I think the 313s survived on Overground services until 2010, with an Overground sticker and the silverlink name and logo painted out. Since all we have for the Bakerloo is the 72 stock it would certainly be a welcome addition