There were rumors that early testers said, the game is bland and open world is empty. So they went back to drawing board. But all is speculation.

Where'd you get these rumors from?

Yeah, the op seems like total nonsense.  This is just a repeat of what happened with Twilight Princess.

I am pretty sure that if NX was coming this holiday season Zelda would be come also, only reason why Zelda is delayed is NX launch. Actually I think we could maybe see Zelda on Wii U at end of 2015 like initial plan was if there was no NX version of game.

The Legend of Zelda for the Wii U was actually getting close to completion. It had already been in beta testing for some portions of the game and was on its way to being released toward the end of the year. Most beta testers felt that the game lacked story and had more of a focus on exploration and dungeons. With such a huge overworld, it at times got painfully boring to just push forward from dungeon to dungeon. While most side quests were fun and entertaining, it had absolutely nothing to add to the story. The beta testers were let down that they weren't more like the recently released Majora's Mask side quests where most in some way pushed the story forward and connected you to the world. 

After getting feed back, Nintendo postponed the game indefinitely to work on the story and to give the npcs more importance, so it felt we were actually helping them as aposed to just running errands. Since the game was overall near completion with the story and sidequests needing fine tuning, a only a few dungeons still left to be completed, Nintendo split the group up, fired some workers, hired new workers, even brought a few over from other groups at Nintendo EAD, and some of the people to the team who had previously worked on Wind Waker HD to complete Twilight Princess HD as soon as possible told "hold fans over" for Zelda Wii U and to have Zelda on the Wii U to see make an appearance at E3 and to hopefully sell more units. Nintendo sees a Twilight Princess remake as a unit selller since it was the number 1 selling Zelda title and its realistic art style as something fans wanted after the tech demo and to bring in more casual players who only care about how realistic something looks. This way when Zelda Wii U is brought out, it will have a hopefully higher number of Wii U owners to market to, since Wind Waker HD didn't sell nearly as well as they had hoped.

http://www.gamefaqs.com/boards/632936-the-legend-of-zelda-wii-u/71903077ttp://www.gamefaqs.com/boards/632936-the-legend-of-zelda-wii-u/71903077

Is Zelda delayed due to NX launch, or NX delayed due to Zelda launch? That is the question...

Interesting excerpt but nothing in there about an empty overworld.

Not at all, Zelda is definitely delayed because NX launch, I am pretty sure Zelda si almost finished and they just polishing it now and waiting for NX release. Remember, in December 2014. they said it will be released in 2015.

All over the internet. The rumor appears at the first delay on March 2015. Of course, the real reason was the NX version as some pointed since the first time.