The best for bitcoin is that Satoshi's identity remains a mistery forever. If at some point his identity were revealed there would be serious chances the impact for btc would be very negative. It could lead investors to panic selling and the mainstream media to create lots of narratives about the hidden goals and purposes of the creation of bitcoin. Maybe it could mean the end of bitcoin, being it replaced by an altcoin, probably ethereum.
Anyway, although we are curious about this matter, I think we should be just thankful for his invention and for all the fruits gathered so far.
If his identity is revealed there will be negative effects on bitcoin, but not to the extent that it is the end of bitcoin, bitcoin will always exist and thrive as long as our needs remain. Satoshi is the creator of bitcoin and he can hold a lot of bitcoins but I guess he can't control bitcoins either, so his presence won't change the decentralized nature of bitcoin either.
Let's say bitcoin is over, I see it's also the end of the entire crypto market, there's no reason why ethereum or any other cryptocurrency should ever replace bitcoin. Not all deserve to sit in the place of bitcoin, centralized altcoins.
That is a risk to be taken if his identity is revealed. We don't know exactly the dimension of such consequences, but I've read some speculations on the internet saying it can be heavily harmful to bitcoin if it happens and it makes sense, because investors would avoid bitcoin if they thought they were being manipulated by a hidden agenda controlled by few individuals, since the proposal of bitcoin is decentralization and going against groups of power.
About ethereum I mentioned it because it is the natural second choice, as eth is the most popular chain for projects/tokens developers.