I'm not sure if this can be done, but it would be nice if there was a window that would summarize the features returning players missed since they last logged in.
The way I imagine it, every major feature added, new skills, major new art, new maps, new NPCs, NPCs with updated/new quests, etc would be summarized and added in. When a feature is added, it will be tracked and assigned a version number or date. The last time the active character logged in would also be tracked. When the window is opened, with a command like /catchmeup, it will match last log in date with features added after that date. The window will filter the list of features to display features introduced after the last log in date.
As a returning player, changes can be a bit overwhelming. Not to mention, you may have some idea how things worked X years ago then feel a bit lost as you realize you effectively have no idea what's going on anymore. I think returning players need something to help them ease back in.
There may be a more efficient/effective way to handle this, but I think something is needed to catch up returning players without having to make a tutorial just for them.