Indeed, c5ae9 does not fix dropped logs (2) or warnings (3).

As for your questions:

1) Yes, the logs will be replayed in order post initialization.
2) no warnings during start up as there are no losses
3) the cost of synchronization is paid during the lifetime of the application whereas state changes occur only during initialization.
Moreover, blocking does not address the problem of logging calls made during initialization by appenders dependent on libraries using SLF4J. Thus, SubtituteLoggers are unavoidable.