FOSS gamedev and creative worlds

It would probably save a lot of bandwidth, and make the game smoother. I'm not sure if Minetest already has it, posting anyway.
Now, if both server and client calculated the movement, much like in the old Quake 3, then the client would just send the server for example, starting and ending points. Then server would check if they are the same as the ones it calculated, and if they are not, it would send a signal to the client, which would make it recalculate the movement. If everything is ok, the movement happens. You can check Quake 3's system if you wish.

That is how Minetest is supposed to work, but it just hasn't turned out like that. It's not a feature, it's something that should just happen.

The server doesn't just send positions or velocity, it also sends acceleration. So the client knows the objects movement at a point to the 2nd derivation. This doesn't help much, as most movements aren't smooth, but have discontinuities at one of the derivations.

Once client side scripting arrives, the server can fully specify prediction itself. Then carts can made follow the track by the client.

Still, it should be a priority. I guess you are hearing the first sentence a lot :D