The Argument For Metro Only Tablets
Metro Windows Desktop
Compatibility Effort high minimal for x86, higher for ARM
Design Effort high minimal
Familiarity (Dev and User) none high
Distribution Costs 30% varies
Distribution Control minimal total
Distribution Channels single, not yet defined multiple existing
User base unknown known
Cool Factor cool not cool

You are a product manager in a Windows software firm. Can you justify the budget required to build a Metro app over simply updating the traditional Windows desktop version?