$70 on Switch is gonna hurt with how they keep their games at MSRP( with the odd sale). That means Switch 2 games 'on sale' are going to be $50 if they follow the industry pricing model ( Nintendo likes to go their own way, but you can bet that's one trend they'll be sure to follow).
It's really only gonna hurt if they try milk it with games previously released on Switch. They try the game they did with the Wii U library on Switch and it's just not gonna work for Switch 1 going to Switch 2. It's one thing to port titles from a dead console with an online and digital infrastructure that is dead as well, to a hybrid console where portability is a big plus.
It's a completely different thing to do that with a successor console to a major hit, when all of your competitors are doing patches and upgrades either free or for a minor cost ($10). It will fall flat on its face. The games won't sell, and people might just choose not to upgrade at all.
We'll see, but if they try to prance around a $70 Switch 2 port of Breath of the Wild as an enticing launch game, that's a huge strike 1.
Add cheap LCD screen and short battery life.
This isn't a big deal, Switch 1 sold gangbusters with a 3 hour battery life on launch and not a great LCD screen. To top it off the dock scratched the screen, and the joycons drifted like trash. Despite all this, it sold due to the hybrid nature being solid and Nintendo firing on all cylinders game wise for almost 2 years straight.
Big thing is that there are no defects this time. People won't be dropping almost $500 after tax for a console plus a game when the controllers drift like trash or there's other issues. The launch consoles need to be solid. The online infrastructure needs to be solid, carrying over your profile and digital library needs to be easy. There should be absolutely no issues popping in your old Switch games and carrying over your saves, everything should be smooth.
And the big thing, they should be providing updates or patches for popular Switch games to run even better on Switch 2. Rewarding your previous community is the best thing you can do in a scenario where you want them to upgrade. Do I expect them to do this for free? Probably not, it's Nintendo. They are known to be greedy. But, I think at this point in the game it has to be reasonable. Either as some kind of tier to the NSO subscription, and/or a separate $5/$10 upgrade if you own the game.
Now I can totally see them repackaging old Switch games with a Player's Choice label, hovering their price around $30-$40 and having it say now upgraded for Switch 2. It's a logical move to continue the evergreen ideal, for completely new Switch owners.