you are confusing ‘high standards’ with ‘specialized’. An MMO server is a highly specialized type of server archetecture. You cannot, for instance expect to take an FPS engine and tell it ‘just stitch these levels together with 10x the players’ and expect it to work as they are 2 very different use cases with respect to replication strategy and synching strategy. UE has done a good job at a generic server arch that serves a pretty wide variety of games. IMO the best post on the subject is: Atlas MMO Framework? - Feedback for Unreal Engine team - Unreal Engine Forums
read what Tim Sweeney spoke of especially '1. Implementing a completely custom MMO back-end framework handling all gameplay logic including object movement, and interfacing it with UE through networking: The client purely runs in UE, and the server purely runs outside of UE, and they are coordinated through a custom networking layer using either UDP or TCP. This approach is generally best for MMOs looking to support thousands of players per server, where UE’s high-precision approach to player movement and collision are overly-expensive compared to tile maps and other simplified techniques.
- Using UE’s built-in functionality for implementing both the client and server components of an MMO, and extending the networking and level streaming code to support new features such as simultaneous connections to multiple servers responsible for separate streaming levels, and coordination between servers to allow seamless movement of actors between them.
NCSoft took approach 1 with Lineage 2 and various other projects, while Sigil Games took approach 2 with Vanguard. For a small project, I’d recommend approach 2, as it’s easy to get up and running in a prototype prior to making engine-level improvements needed for scalability.’
if you played (or tried to play) Vanguard with the lag, you will see why its generally not a good idea to use the ‘standard dedicated server’ with an mmo.