Horizon looks amazing. Zelda has got that wow factor though. This might be the best looking game on Wii U! It, in a lot of areas shown, looks as good as PS4 and Xbone games!
To be fair, many parts also look like PS360 games. It's like a gen 7.5 in terms of graphics.
OP - But to me Zelda has more of a wow factor because I'm a huge Zelda fan, and with Zelda, it's an old franchise, so seeing a huge change from the 18 year old 3D formula is more of a Wow than seeing a new IP, because there's less to go off of in terms of what to expect from it in a way.
To be even more fair, it's still an E3 demo. But I agree, some things don't look good at all. Like the trailer when Link gets on a horse and all the colors are just washed out, the pop ins and that pine tree falling over. But then again, it's stylistic so I guess that accounts for some things.