Going to start off by saying I don’t think S Stock are bad trains by any stretch of the imagination - they’re a massive improvement on what came before them.
However, they do not feel their age, and I mean this in a negative way. Despite entering service in 2010, the interiors of the trains feel like they’re from the 90s with their dim yellow halogen light tubes, worn seats/armrests, and lack of any digital screens, along with a very dated colour scheme. With the New Tube for London on the way for the Piccadilly line (and hopefully the Bakerloo), I think it’s appropriate that TfL should start to look into how these trains can be brought up to a similar standard.
At the very least, the seat moquettes should be replaced, and new LED lighting should be installed. Both of these changes wouldn’t be too costly to implement.
Wishful thinking would also see the dot matrix replaced with screens similar to those on the 345s, with much better way finding.