I will post something now, if I think about something else I will put it in a new post or edit this one if no one posts until then.
Pros
Fun over graphics: They know that good graphics doesnt mean good game, so they go right into the core and focus more on the fun, letting graphic quality for later. In the end, it still very good (IMO these people talking about 1080p is a must or things like that are being a little spoiled by the industry).
Good franchises: Nintendo have proven that even if third-parties abandon them, they can resist for a long time and will not fall instantly like some other companies would.
For all ages: They do games that can be played by everyone without being boring, I call it "true videogame", since thats how old games are, and IMO that how it should ever be. Im not saying that all games must be like that, but at least 50% or 70% should.
Memorable music: What could I say? They havent lose their good taste over all these years and some of the most iconic musics comes from Nintendo (I've said some, not all).
Free online service: While all other services right now (PSN was free too, but will be paid in the near future if I understood it right) make you pay to play online, they give it for free. One of my cons would be that friendcode system, but they finally fixed that in Wii U and 3DS.
Innovation: They ever come with new ideas, not focusing only in graphical update, sadly other companies copy these ideas after seeing it. Even if they say that it never would make success, when Nintendo do it and it indeed make success, companies come and do the same thing. (Vita and Smartglass acting as a controller like Wii U Gamepad, PSMove being a Wii Remote clone).
Cons
Region Lock: This is obsolete and nothing that they say will be enough, they give excuses about rating and updates, when they can do all updates be universal. Also games need to be imported if its from another region, kids doesnt have credit card and thus they can only get it with a parent permission, so "rating fault = bullshit".
Virtual Console choices: Im not talking about which game they choose, but how they decide which system to put in 3DS and Wii U. GB, GBC and GBA makes sense to be in 3DS, but then they go and decide to put GBA in Wii U instead. So here is my idea: why they dont add Virtual Console that are compatible with Wii U AND 3DS?
Neglecting some older franchises: Sometime ago they were focusing too much in some franchises and forgetting other franchises, but recently they brought Star Fox and Kid Icarus back. Now Im waiting for a new F-Zero, Ice Climber, Balloon Fight, a real new Excite Bike and maybe they could add Duck Hunt in a new Wii U Play.
Third-parties: I dont know whats the problem, but they really arent receiving the same attention as before from thirds, this is the core problem for Wii U right now, since I cant see any other.