Concrete is simply the mass production medium of the time, many of the patterns and moulds used in Barbican for example feature pretty timber imprints, scalloping patterns, painstakingly pick-hammered textured panels, or pleasing swooping shapes.
Further there is always space for glass, brass, Terrazzo and lighting.
Sam's design does feel cold, unnatural and broken, definitely not what brutalist living is about.
https://www.theguardian.com/artanddesign/gallery/2016/feb/22...
https://www.structuralrenovations.co.uk/portfolio/barbican-e...
https://www.barbicanliving.co.uk/barbican-story/construction...