Completely disagree. The N64 games looked polygonal, blurry and ugly – even back in the 90's (just like PS1, which was basically a SNES with CDs). It was the first 3D generation and they should have stayed with 2D during this time. First when DC/PS2/GameCube arrived, 3D games looked decent.
Your argument that Wii U always looked a gen behind is ridiculous. Which comparable PS4 game looks better than Mario Kart 8? Tropical Freeze is even one of the best looking 2D platformers to date. Of course you can make scripted scenes that look impressive, but which need many GB space (I look at you TLOU), but that's not the way to make fun games with gameplay focus.
I believe that many Wii U games will be fun to watch and play in 20 years, while N64 games aged very very bad. It was just too early for 3D.
In case of legacy for the video game industry, the N64 clearly wins with 3D camera control, analog stick, rumble and 3D game design like in Mario 64 and OOT. The Wii U gamepad wasn't that revolutionary for games Nintendo may has hoped.
The Wii U wasn't even fun to play 5 years ago.
But in all seriousness, you might want to rethink your first paragraph, and I'm going to tell you why:
Saying something like N64 wasn't good enough for 3D, so it should have done 2D is about the same as saying NES wasn't good enough for 2D, so it should have done text adventures.
You can't skip the first half a decade in 3D console gaming and expect to be at Dreamcast level. Much of what made 3D games great was invented during the N64 and PSX generations: this is not just from a mechanical and design perspective, but also from an animation, texturing, and modelling perspective. Some stuff stuck around (Nintendo still uses scrolling textures to this day), other stuff didn't (Pre-rendered textures and single stick aiming isn't often used anymore), but at least devs got to see how it all worked on the market over 5 years. 3D engineers, animators, and artists grew in skill and quality throughout the generation.
Relativity is everything: when then N64 came out, its graphics were mindblowing to most gamers. Waverace 64, looks pretty crap today, but people were going nuts over that one.
I recall being quite impressed with GE007's graphics when I first played it. While the game looks and plays very outdated today, when it first came out, it felt extremely cutting edge, so much so that it was hailed as the best game of that year, and it was up against massive releases such as Final Fantasy 7. Goldeneye sold 8 million copies, and it wasn't some massively marketed game that was shoved down everyone's throat like DKC, Mario, and Zelda. Instead, GE007 was a sleeper hit that released to very minimal fanfare, but gamers LOVED it, and it became the biggest sleeper hit success story until the Just Dance series about a decade later.
Mario Kart 64 is another success story as it replaced the very popular original Mario Kart as the game of choice to play in the franchise. At first glance, that may seem obvious; sequel replaces original? But Mario Kart Cube and Mario Kart Advance both failed to supplant Mario Kart 64 as the primary Kart game. While Mario Kart DS became a serious challenger (and sold WAY better in the end), it wasn't until the monstrously successful Mario Kart Wii came out that we had a clear preferred successor to Mario Kart 64. As a note on Mario Kart Wii, it's not only the best selling unbundled console game in history when considering only single platform sales, but the game sold 40,000 units last quarter, more than 11 years after release, and 7 years after its generation concluded. Yeah, Mario Kart 64 was supplanted itself, but it took four games and one of the biggest success stories in video game history to do it.