Not a big deal at all. It's not your content to begin with. They can do what they want with it and they'll do just fine without your so called advertising. I love Wii U and am looking forward to the new 3DS on their own merits.
This is the type of thinking that has nearly crippled the internet with SOPA and the loss of Net Neutrality.
To avoid a very long winded speech about copyright and fair use, let me summarize...As soon as Nintendo, or anyone else, releases a product for sale, and it is purchased by the consumer, the consumer can claim ownership in some capacity. They bought it. They can do with it what they please - they want to break it, eat it, give it away, share it - it is THEIRS to do so. Copyright comes in to play in terms of "sharing" this with others. In terms of showing this content to others, video games are not movies or music. They are classified differently because they are interactive, meaning that one cannot get the experience of playing a video game by watching. Unlike other forms of media (movies, music) that are passive.
*quick side note* there is something to be said for people who just post all the cutscenes or just put up the entire game without commentary, or anything else **
Once a youtuber, blip user, twitch user etc puts up a video with commentary or edited in some way, the user has ALTERED the original product, meaning that it is NOT the same as if you or I bought it in the store. it is its own unique experience. So because of this, copyright is generally not claimed - it falls under the fair use clause which stipulates that a medium may be used for review or parody purposes (as well as a lot of other legal stuff)
The reason this is so blown up is because Youtube is very friendly to copyright holders (for fear of getting sued) so anyone at any time can place a "claim" on a video. Youtube then determines if it is legit. The problem is that this results in a "strike" on a youtuber's account. 3 strikes you're out. YOu'll notice that Twitch TV and Blip are safe havens for a lot of this - it's because they are not as friendly to copyright holders as youtube. For now.
Anyway - before you start defending the video game companies' "rights" to their games, start thinking about reselling or lending/renting games - if they had their way, you couldn't do that either. The only way you could play their games was to buy it yourself at the MSRP. *See Microsoft, circa 2013 Xbox One Reveal*
This new 60/40 split is pretty stingy. Some partnership programs iffer up to 90% ad revenue, so Nintendo is just trying to cash in.
And as for Nintendo not needing free advertising? The Wii U has been out over 2 years and sold less than 10 Million units WORLD WIDE. That is worse than the Gamecube. There are still reports of people thinking the "Wii U" is an add-on for the Wii. 3rd party titles are almost non existant (or just really bad ports). So the 3DS does great...but Nintendo shouldn't look a gift horse in the mouth when people are showing off Bayonetta 2 or some other "must own" game for the Wii U that 85% of the casual market (who make up the majority of gamers, especially on Nintendo) doesn't know exists. And as for Youtube not helping? Tell that to Minecraft, Five Nights at Freddie's and Goat Simulator to name a few.
*gets off soapbox*