^ those are all great points, except i find the gamepad to be very friendly, and smooth. (WW and Pikmin 3 made great use of it.)
without knowing your tastes in games, id say a huge reason is the Virtual Console. There are so many games out now, new and old, no one can say that there isn't anything to play on the wii u. Smash Bros, Hyrule Warriors, MK8, Nintendoland, all in HD, all are a blast.
if you do upgrade, i suggest getting the Deluxe, 32 GB set. the memory goes pretty quick. Super Luigi U took quite a few GB