I thought about this a while before and I think this is a very plausible feature. Exploits revolve around the player (most of the time) and making the server authoritative of the character dissolves many prominent exploits (hitboxes, teleportation, tools, etc.).
Server-sided characters would be a great extra layer of protection, especially for games that don’t revolve around moving collidable objects (so it won’t cause any disagreements).
Would be useful for training AI, and I’ve also wanted this feature for recording player speed runs and replays.
Necro bump but this would help a lot with netcode in general. The physics engine seems to be fully deterministic so it would be very handy
I would like to bump this again to express interest in this feature. It’s great that we’ve now got pausing physics in studio, and I’d love for this to be added too.
You can already do that. It’s not pretty when the server controls everything because without any client prediction, the movement is very much like gaming was in the 90s where there is a lot of delay in inputs and movement. It solves the exploit issue you mentioned with players cheating movement, teleports, etc., but makes for a terrible gaming experience for everyone else not cheating. 
This looks like this is a planned, upcoming feature, as they recently released the ability to pause physics in studio, along with the inclusion of a new method under the WorldRoot class, StepPhysics. Looks like it’s not able to be called in the local or server scope yet.
I’m hoping plugin security level is a temporary measure only too
Why is this not a feature yet?
Allegedly it’s coming and exists as plugin security only for now. Hoping it comes soon
Bump.
I need this and so do many others that I know!
Bump.
This would be awesome for server authoritative player movement!
Bump!
Server authoritative movement is still the way 90% of games handle player movement unlike the 2006 Player controlled movement.
This topic needs a bump! This would be such a great feature and I hope Roblox listens to us and adds it one day.
Bump.
This couldn’t come sooner.
Bump. We all need this feature. Chickynoid has proven that even without direct access to api’s, character physics can be verified through server without any significant performance costs
It’s peak 
unfortunately StepPhysics seems to be left on PluginSecurity on purpose(see New StepPhysics Plugin API)
My thoughts are it’s good but it’s not great because if anyone finds a bypass to server authority it’s pretty much going to lead to an even worse era of exploits. Every time they push something to counter exploiters… the exploiters push back even harder. It’s like a game of tug of war.
This is like saying “If anyone finds a bypass to Filtering Enabled it’ll be horrible”, the entire point is that is becomes impossible to have the Client tell the Server what to do, like what Filtering Enabled did by completely preventing Clients from arbitrarily replicating Instances and Properties to the Server. This should get rid of the remaining stragglers by eliminating the Network Ownership system and a few other places where Filtering Enabled was (intentionally) not respected.
