I'd expect more 3rd party support earlier in the product cycle too since the Switch concept has proven to be successful.
There's probably a shit ton of PS4/XB1 era content that a lot of devs would want to bring over and also titles like Street Fighter VI that would make sense (3DS launched with SSFIV).
Final Fantasy VII Remake, Elden Ring, Red Dead Redemption 2, Resident Evil 4 Remake, Street Fighter VI, Call of Duty latest game, Madden NFL I could see being on the next Switch as IP that aren't on the current Switch, several of them maybe even very early on.
I actually would like to see that happen, but I’m not holding my breath for even half of those coming to the successor, launch or otherwise. Street Fighter VI i can see happen (Street Fighter has legacy with Nintendo consoles). RE4Remake is possible but who knows, at least there’s history there as well with the original originally a GameCube timed exclusive. Kingdom Hearts, maybe they’ll not be lazy this time and release all of the games digitally and/or physically on the successor. Modern Final Fantasy games on the Switch successor? It’s possible if Square isn’t hand tied by Sony’s deals. RDR2 and COD? I don’t know if I can go that far. Im not sure Rockstar cares enough of a Switch successor. I know Microsoft promised Nintendo will get COD in the future. But if they don’t finish their purchase of Activision Blizzard, I’m not sure if Activision Blizzard, independently, will care enough to bring COD to the Switch successor. Same with EA and Madden. They’ve had years to get one onto Switch but don’t care enough to port even one game. They’ve been lazy with the FIFA Legacy titles on Switch so how can I expect any better even with improved hardware?
Im hoping the successor will have improved third party support (if we’re going by the rumored/leaked specs of the console). But I wouldn’t be surprised if we see only a minor improvement in that department and mostly see the same support we’re seeing right now. Indies, A-AA games, Square’s HD2D games, that once in a while impressive PS4/5 port of a previous big game (I.e., Witcher 3, Nier Automata, Persona 5 Royal, Doom, etc.).
Ultimately, in order to maintain the great success from the Switch, Nintendo will have to carry the load once again with its own big titles.