I am very excited about the new Nintendo Switch and for good reasons and Let me explain why.
I didn't own the Nintendo 3DS XL or any previous portable console, but I can certainly understand the benefits of playing on a portable device because I play games on my tablet and mobile phones. There is something more personal and convenient when playing games on a relatively small and compact device. It's like with mobile phones, you feel that it's yours, you enjoy knowing that you can take it with you and play it anywhere you go or in another room in your house.
The Nintendo Switch actually offers two ways for playing games, either on a big screen or detaching it and playing it like a 3DS portable console. So you actually don't have to choose, you can enjoy them both. I think that portability is one of the main reasons why the 3DS and many other portable gaming systems are so popular. Just imagine instead of seating in front of a large TV or a computer, just lying in bad and playing your favorite game. It can be really comfy and contribute to the fun factor in my opinion, which is something that is related to the compatibility, and where you actually prefer playing a game.
Exclusive Nintendo Games
I think that what makes Nintendo and its consoles so appealing is related to their exclusive titles. I personally wouldn't even looked at Nintendo without the exclusive titles. Nintendo is the only company in the world that brings me childhood memories and keep bringing titles that reminds me the amazing games I used to play when I was younger. I always loved RPG games and I am fanatic about multiplayer games. Nintendo has some of the most compelling titles that I am really excite dabout, including the amazing grindy multiplayer RPG title Monster Hunter 4 Ultimate and Super Smash Bros., the amazing competitive brawler games. I have the PS4, and there isn't any games like that on any other console. For example, I really wanted to play a brawler on the PS4, nothing like Super Smash Bros, there was one quite similar on the PS3, but it wasn't revived on the next-gen consoles. Monster Hunter 4 Ultimate is like playing Destiny, but only with boss fights where you can team up with friends online and go kills bosses and get new gear.
I didn't even mention all the great other titles like Zelda, Pokémon, Splatoon and many others. I have the PS4, I bought many games, and I can tell you from experience that there are many games that I stopped playing after two hours because it was so boring. My enjoyment in games has nothing to do with visuals, it's the gameplay that matters. I actually love the non-realistic comic/cartoonish like visuals, and this is another reasons why I love Nintendo games so much- a childhood fixation I guess.
So When the Nintendo Switch comes, you can rest assured that there are going to be many many great new titles for it, many exclusives.
A Portable Gaming Device with a Large Screen
Just imaging being able to play Super Smash Bros. on this system like a portable 3DS device with even better visuals and on a 6.2-inch multitouch display, which is much larger than the 4.88" found on the Nintendo New 3DS XL device. This is going to bump up the experience times fold.
I've read some people comparing the Nintendo Switch to a tablet. Yes, it's like playing with a tablet, but the main difference is that you have those side physical controllers, and all the games developed for it will take advantage of those controller, much more fun to use than playing an Android game using a touchscreen interaction. Furthermore, most of the mobile games are designed to make money from in-game purchases, that's the most popular business module and that ruin a lot of games that are heavily dependent on microtransactions. This is not the same as Nintendo games, where you buy them for a full price and don't have this microtransaction crap that ruin the gameplay experience, for every game, but for most games.
The Best Alternative to the 3DS
Nintendo 3DS is the most popular gaming device on the planet alongside the Wii U, Xbox One, PS4 and PS Vita. Over 60.4M units were sold, more than the PS4 (45.8M, stats from vgchartz as of 29th October 2016).
I think that people just love the physical and personal connection with the device. The main problem the 3DS has is that its screen. The 3D effect is great, and probably one of the main reasons to get a 3DS device, but I think having a larger screen and a more powerful device will appeal to many gamers more than the 3D effect (but I might be wrong on this).
Summing Things Up
So in my opinion, the Nintendo Switch has a huge potential. It brings all the great things about modern consoles and portable gaming devices into a single device. I am very excited about this new upcoming gaming system and seriously thinking of getting one myself.
Hope this long explanation helped a bit.