Bloodborne (very well may be the game of the generation), Infamous, and New Super Mario Bros U are the 3 best exclusives in my book. Bloodborne is by far the best game on any platform this gen imo.
I think the Wii U's library is pretty solid actually, it is doing exactly what Nintendo wants (as far as games) because lets face it Nintendo does not care about 3rd party at all.
Library's
PS4>XBOne>Wii U
Exclusive Library
PS4>Wii U> XBOne