I was thinking there could be a 'Record Delay' feature that would add a delay for when you join a world and when it starts recording.
You could enter a value, lets say for example 10 seconds, and that means when you join a world, you have 10 seconds before the ReplayMod starts recording. There could be a limit of 60 seconds max.
Just though this may be useful for people to make sure they have what is needed in their inventory, they are in position to start etc before they start recording. I dunno, it's just an idea :P