Old launcher would open log window / console window when playing. Launcher Settings Keep Launcher Open AND Open output log both selected as in old launcher. Console stays up with no changes and Log window opens and is blank until world loads then displays beginning of log file from START of launcher and stays there. You can manually scroll down in log window and the log is there but it does not stay current.
Ummm - So Windows is the same as Mac - Hmmm - sounds like you guys really screwed up then if both very disparate platforms are affected. Heh - at least restoring the OLD Launcher and then having the firewall deny access to Mojang allows me to play using the Old Launcher Offline...
Hopefully someday you will actually fix the bug. Let me know if you do.