It is sufficient to only wait for the previous (H-1) block to be consensus-finalized, because the following are sufficient to build the executor for H:
- DB-state reader for
H <= 2,
- finalized state diff for
H - 1,
- transactions for
H.
This way we can start deferred execution for H earlier, because we don't have to wait for trie updates for H-1 to happen.