I think part of the problem is that there were a lot of games out at Wii U launch, like 20+ core oriented titles (almost entirely late ports, of course), so instead of one third party title selling a million copies, twenty third party games sold 50,000 a piece. Compare to the Wii launch where you only had basically two games, Zelda and Red Steel, and you can see where sales would congeal around those two unlike how they fractured around the many at Wii U.
It's funny how often Wii owners repeat that "late ports" excuse to explain why the Wii U had such a rough start. If only those the Wii U got new games, then it would have sold so much better.
Chasing Aurora
Little Inferno
Nano Assault
New Super Mario Bros. U
Nintendo Land
Sing Party
Tank! Tank! Tank!
+ Darksiders II
+ Mass Effect 3
+ Namco Bandai Tekken Tag Tournament 2: Wii U Edition
++ Ninja Gaiden 3: Razor's Edge
++ Batman: Arkham City Armored Edition
++ Trine 2: Director's Cut
++ Warriors Orochi 3 Hyper
+++ Assassins Creed III
+++ Call of Duty: Black Ops II
+++ Disney Epic Mickey 2: The Power of Two
+++ EA Sports FIFA Soccer 13
+++ ESPN Sports Connection
+++ Game Party Champions
+++ Just Dance 4
+++ Madden NFL 13
+++ NBA 2K13
+++ Rabbids Land
+++ Scribblenauts Unlimited
+++ Skylanders Giants
+++ Sonic and All-Stars Racing Transformed
+++ Transformers Prime
+++ Your Shape: Fitness Evolved 2013
+++ ZombiU
+ No frills ports of older games
++ Upgraded versions of older games
+++ Recent games
There are seven titles that could be called "old", but at least four of those titles were enhanced ports. The majority of those 30 third party titles were brand new. The Wii U almost got each major publisher's top games plus a number of family games ideally suited to the Wii audience.