According to Digital Foundry the Switch version at E3 did run better than the Wii U version, so no you're not alone. Plus the Switch is more powerful than the Wii U paper.

Here is a comparison between Switch and Wii U:

https://youtu.be/_ZuxgLcgpFk

I think we already have the answer!

There's no way of knowing right now if the differences are due to the change in console or just having 7 more months of development, but there is a clear difference between the graphics in the current Switch demo and the graphics in the old Wii U demo.

Switch version looks better. The WiiU version looks too bright.

Its just you. Look at that draw distance.

That's what I'm thinking. It's been almost a year since the E3 footage, we can't reliably use that for comparisons. If it's VGA footage, then fine (Seen a lot of comparisons using the intro. The Switch version doesn't look much better, it looks very different).

I'll wait for DF's review. I like their analysis the most.

That's a huge difference, draw distance, color richness, occlusion and lighting (look at the prismatics made by the rays of sun on Switch), textures, filler and lack of blur to cover less PP effects. It's really, really different. Switch version looks amazing, great draw distance too!

The Switch version looks indeed better. It is less blurry thanks to the higher resolution. When you pause the video at 0:42 for example. You can see the grass on the ground where on the WII U it is missing. So, a better draw distance.