Kingreaper
Adventurer
The system decides how the game will actually play.
The adventures decide how the game will be perceived.
If you want to pull people in, you need the adventures. Even people who don't use them will often judge it based on them, directly or indirectly.
If you want to keep people, and have the game last long term, the system is more important than the first released adventures.
But there's no point in one without the other for 5th IMO. If they don't have the good adventures, people will assume it's only playable in the boring way the adventures work. And if they don't have a good system people will know that due to the playtest, and won't bother staying with it when it's released.
The adventures decide how the game will be perceived.
If you want to pull people in, you need the adventures. Even people who don't use them will often judge it based on them, directly or indirectly.
If you want to keep people, and have the game last long term, the system is more important than the first released adventures.
But there's no point in one without the other for 5th IMO. If they don't have the good adventures, people will assume it's only playable in the boring way the adventures work. And if they don't have a good system people will know that due to the playtest, and won't bother staying with it when it's released.