At this point, I really do think the Wii U version should be cancelled. Keep in mind that this game is still in development, so it's very likely that Nintendo might end up just dropping the Wii U in favor of the Switch version being the finished product. A lot of people don't want the Wii U version due to the bad framerate. Plus the Wii U is dead anyways. So releasing a game on a dead system with bad framerate just kill the Wii U version in sales anyways cause no one likes bad framerate. That said, there's no point in Nintendo even releasing such a dull version of the game.
Everyone is going to want the Switch version because they're gonna the new hardware, the better framerate, and the best experience. They're not going to waste money on bad framerate. So cancelling the Wii U version is most logical and beneficial move for Nintendo.
1) It means the thunderous success of the Switch, as millions of units will constantly be selling lightning fast, making Nintendo lots and lots of money!
2) The Wii U is dead, the past. It is the Switch's time to shine now.
3) The Wii U version will just be a burden to Nintendo.
4) The Switch version is the superior one and the most logical to buy. Rendering the release of the Wii U version pointless.
Twilight Princess sold over 7 million units on the Wii and only around 1.5 million on GameCube. Some of the people who bought a Wii U in hopes of Breath of the Wild will buy it on that system, but most people will buy into the Switch hype and get it for the newer hardware instead. A dual release won't dent Switch software sales.
That was a different time. Also, the Wii sold well because there was no Gamecube game to interfere until December 2006. I mean the Wii had nearly a whole month to sell. Which is why it sold so well. A lot people bought the Wii for the Wii version of TP because they didn't want to wait until December.
This time is different.
Both versions of BotW are set to release at the same time, on the same day. So this means anyone who doesn't have the money to buy a Switch will buy the Wii U version because they afford a Switch and don't want to wait until they could to get BotW. This will get in the Switch's way, causing a competition between the Wii U version and the Switch version. But not by much though. As the only reason why anyone would buy the Wii U version over the Switch version is if they can't afford a Switch and refuse to wait til they do to get BotW. So only on day 1, the Wii U version will sell more. Then after that, the Switch version will sell more, killing the Wii U version.
So basically, like I said, the Wii U version will just end up being a pointless burden for Nintendo. Which is something Nintendo doesn't want right now due to they're money problems. Making the dual release strategy unwise this time around. It worked for TP because back then, they didn't have to worry about money problems, not mention both original versions of TP released in two different months. Again, the Wii version being a month before the Gamecube version. Besides, look what happened to the Gamecube version anyways. It was a burden. And it will be same case with the Wii U version of BotW, only a little different this time.
That said, it would be wise for Nintendo to just cancel the Wii U version. Otherwise, it will just be a burden getting in the way of things.