Extensible - Wyvern has a unique event model that lets you control every aspect of the game. There is practically nothing in the game that you can't extend or modify with a little of your own code. Many magical spells only require a few lines of code. The Wyvern platform is extremely flexible. Simple - The artwork is deliberately kept very simple.
Wizards can add their own artwork to the game.
It's easy to create new artwork for the Wyvern platform, and doesn't require expensive tools or training. Scalable - Wyvern allows characters to wander from server to server. Servers can be linked together with custom immigation rules. Any number of servers can be linked together to create a really large game world. Because MUD areas are created by their users, they tend to grow in surprising directions.