The recommended specs for Windows are overkill. Keep in mind that information like that can result in customers thinking, that their setup isn't good enough for smooth gameplay (won't purchase).
As already mentioned, the specs will vary but this is what I'd go for on Windows systems:
MINIMUM:
OS: Windows 7 or newer
Processor: Dual Core (2.0 GHZ)
Memory: 2 GB RAM
Graphics: Dedicated graphics card with 512MB VRAM
DirectX: Version 9.0c
Storage: 900 MB available space
RECOMMENDED:
OS: Windows 7 or newer
Processor: Quad Core (3.0 GHZ)
Memory: 4 GB RAM
Graphics: Dedicated graphics card with 1024MB VRAM
DirectX: Version 11+
Storage: 900 MB available space