What is the quality of multiplayer on the Switch*? I've wanted to pick up BotW and Odyssey for the longest time but I've been weary of buying new consoles since I hardly got use out of the Wii U (I traded it in before BotW's release to get more value). If I pick up friendcodes here and ideas for other games I'd consider it again.
*This goes hand in hand with the question 'how different is Splatoon 2?'
I personally love my Switch, and I did not regret getting it one bit. Super Mario Odyssey is amazing (so is BotW), and unlike the Wii U, the Switch is growing quite the library, both first and third-party. There's Splatoon 2, Octopath Traveler, Skyrim, DOOM, Wolfenstein II, Mario Kart 8 Deluxe, Paladins, Bayonetta 1/2, Fire Emblem Warriors and much more, including Pkemon Let's Go Pikachu/Eevee and a NEW Smash Bros. game coming December 7th. There's even plenty, and I mean PLENTY, of good indie games. Plus, you can take all those games ON THE GO! I have a Wii U, and I can safely say that the Switch is MILES TIMES BETTER! More power and portability make for a pretty good system.
Now, as for the online, it depends. Nintendo does not have dedicated servers for their games like Mario Kart 8 Deluxe and Splatoon 2. This means that the games rely on Player-To-Player, so the connection depends on that of each player's internet. As said before, the online paid service is coming, and while paying sucks, you pay 20$~ for the whole year (compared to PS4 and Xbox, this is lovely) and you get some NES (whether it's a handful each month or a whole library, like Xbox's Game Pass, is beyond me).
For Splatoon 2, it depends on what you mean by different. The core mechanics are still there. Splatfests are still there, and there's new content being spewed out each month until the end of the year. In Splatoon 2, however, there are more weapons and more KINDS of weapons. The specials are less game-changing and more balanced (If you liked the Kraken, RIP). Getting the abilities you want for your gear is much easier, and now it contains a Zombie-like mode called Salmon Run (it's reallyyyyyy fun and HARD SOMETIMES). There's a new Ranked mode called Clam Blitz (it's rumored that there's more to come), which is where you throw clams that are scattered everywhere into your enemy's basket. And finally, my personal favourite, there is purchasable DLC which is a single player campaign called "Octo Expansion," where you can play through 80 difficult challenges as an Octoling, so if you purchase that, you'll be much happier than sticking to the still-kind-of-easy-but-better-than-Splatoon-1's single player mode.
Is Splatoon 2 different? As I said, it depends. I personally see it as a brand new game, but that's also because I haven't played the predecessor in over a year. I think there's enough content to make it new and improved. If you liked the first one, you'll LOVE the second one.
I hope all this makes your decision a little bit easier. Hope I helped!