The answer to the initial question is, as stated above, “Right now world origin shifting is not supported in the multiplayer games.” It has been hinted that this will change in the future, but no timeline has been set. As for the second part of the question, “Should I try to fix world origin rebasing so that it works online too?” -This would be great, if possible, and could even be released on the Marketplace as a plug in (for incentive).
Focusing on single player games, the value was changed from being around 3.5-4 km from the world origin to 20 km from the origin in UE 4.8, so if you are experiencing an issue with your animation based aiming jittering within these parameters, please re-examine your set up as this has been proven to work for UE4.8 on.
However, if you feel this feature is not functioning as expected, please provide steps to reproduce the bug on our end and we will investigate to see if World Origin Shifting has regressed and needs to be corrected for single player mode in current releases of the engine.
Finally, since this thread is getting long, and away from the initial question, please start a new thread to discuss the proper set up for Animation Based Aiming for true first person. Here’s one solution posted by a user on reddit that I feels addresses the issue:
https://www.reddit.com/r/unrealengine/comments/2znb6k/creating_aiming_for_true_fps_project/
While discussion of this and other solutions is encouraged, please start and discuss this on a new post so those solutions won’t be “buried” within this thread.
-Thanks