In 26 years I'd never noticed this about the Simon Foster depot... but yes, now I look it's quite outsize! Transport Tycoon scales are all over the place (even before idiots like me start adding overscale trains into the mix), I always feel you end up chasing your tail trying to fix them so I tend to just stick with the same sizes as the original objects. The way I'd consider solving it is:
1. Make the depot buildings more impressive to match their size, the 1890-1936 depot looks a lot more natural because it's based on a much larger real-world prototype.
2. Build a town set that fixes some of the most underscale buildings such as the three-story "modern" flatblock.
Maybe I'll have a play around with the depots, past a certain point you end up with something too small to realistically contain a double decker bus or line up with the standard catenary so it might be more of an approach of making the buildings look like they represent a larger and more impressive prototype.
Kamnet, I think this might be one of the divisive elements of the set . Personally I think a lot of roadsets look too flat, they are technically more accurate than the original roads when you consider the height of a house but I prefer the exaggerated effect. Ignoring my own opinion, I'm currently about equal in comments for and against the curvature . For some reason it does look a little too strong on the non-junction corner, maybe I might see about toning that down if it starts annoying me.