Why editing the memory of the game client works? Why so many "Hack protection" tools coming with the clients?
If I were to design a client-server game, everything would happen at the server (the simulation of the game world) and clients would be only passive consumers receiving status updates of the part of the world near their characters, sending only some information like keystrokes or move/action commands. Maybe I missing something here, but with that design, any hack like raising my STR by 200 in the client memory (if the value is present at all), just won't have any effect.
The only explanation I can think is that games in which memory editing works let parts of the simulation run in the client and the server then just synchronize all the clients periodically. I can understand that design for Real Time Strategy games with a fixed number of players once a match is configured, but, why in MMORPGs? Is it a strategy to reduce server load?