It would be very useful to have a module (placed on map) which saves players stats (location, position, gear, etc, etc...)
So that when you log out of a persistent server you can rejoin later with everything that you had before and carry on playing.
There could also be the option to set how long the player save file stays on the server, E.G. The players file is automatically deleted after 30 days of inactivity.
This would give people with great ideas but limited scripting knowledge the ability to create larger and longer lasting missions with ease.

I have been using a great script (Addon-Free Stat Save System [Script]) but it has recently stopped saving stats since the last update, so I am trying to keep everything as close to BIS content as possible to avoid spending all my life in the editor lol :-s

So a nice stable MP stat save module (by BIS) would be the icing on the cake for large scale or persistent mission making :-)