Allowing the user to configure how strict transaction_replay would help improve the likelihood of transactions being successfully replayed.
One common case is that the OK packet in response to an INSERT contains the auto-generate value for an AUTO_INCREMENT field. This can cause transaction replay to fail if the same ID is not generated during the replay. Depending on the client application, the actual ID returned in the OK packet might not be used and the LAST_INSERT_ID() function is used instead.
This option could also modify the checksum calculation algorith to calculate the resultset checksum in a way in which the order of the resultset rows is not critical. This can happen if the SQL statement doesn't have an ORDER BY clause and the implicit ordering of the database is used. This could be done by multiplying the checksums of each packet in the responses instead of doing the checksum on the whole result.