Now, thanks to the latest issue of Famitsu, we can say with certainty that the game is exactly 50% completion. That would explain why Capcom set a very vague 2023 release, let alone few in-depth details about the collection's content.
With development halfway complete, it stands to reason this time might be spent solidifying additional content and features. Unfortunately, the Famitsu coverage doesn't provide further details.
For the time being, we can only wonder. Will we get an extra game mode like the previous Legacy Collections? What about online multiplayer? Are they going to restore the Boktai cut content from Battle Network 6? Revised, retranslated scripts? (I know Battle Network 4 would benefit from a new one)
We'll have to wait a little longer to find out.