Thought it would be fun to do. Based on market performance (NOT game library):
Sony Playstation 4:
North America: A, Europe: A, Japan: F
Sony Vita:
North America: F-, Europe: F, Japan: C
Nintendo Wii U:
North America: D-, Europe F, Japan: F
Nintendo 3DS
North America: C+, Europe: C+, Japan: A-
Microsoft XBox One:
North America: B-, Europe: C-, Japan F-