The problem is that Nintendo makes both Home & Handheld systems, and normally use a similar concept for each during a generation. This will continue even more so in the future for the following reasons:
A) Handhelds have become much more powerful and 3DS can nearly produce every Wii U game Nintendo creates, even if it's a bit smaller scale.
B) Development times have increased due to much more powerful systems. They can make games quicker by sharing concepts which is why Nintendo recently merged their teams.
C) At the end of the day, Nintendo is still a business trying to make $. If they can Make 2 versions of most of their games and people will still buy them, why wouldn't they?
M&S at the Olympic Games, Sonic Lost World, Resident Evil Revelations, Super Smash Bros 4, & Lego City Undercover all are (will be) on both 3DS & Wii U. Then you have Starfox 64 3D, Zelda OOT 3D, Donkey Kong Country 3D, Zelda WW HD, which are simple remakes of games and easy money.
Finally, you have the games that borrow concepts from their other current Gen system:
- New Super Mario Bros 2 & New Super Mario Bros U
- Mario Kart 7 & Mario Kart 8
- Super Mario 3D Land & Super Mario 3D World
- Animal Crossing Wild World & Animal Crossing City Folk
Expect this trend to follow with more games on both systems, more remakes, and more borrowed elements.
You can prevent getting tired of "nothing new" by only buying 1 Nintendo system or 1 game from each shared concept every Gen. That is what I've decided to do.