Minecraft's combat system always reflected its simplicity, and basically amounted to clicking things until they died. It's just been overhauled with a game update centered entirely on combat. Ideas that seem simple become more challenging when you have to account for lag.
Much of what defines the design of the combat update – and Minecraft in general – is really about networking, however. When you attack, your client sends the mob or player's ID to the server, and then the server calculates the combat mechanics. This means that there is no physical sword-swing in the world, unlike in the likes of Skyrim. The reason for this network design is that, rather than the server, your client has a lot of authority over your actions, because loading the world from the server is very resource-heavy. Minecraft would feel less than fluid, especially for those with bad connections, if the client had to wait for the server to perform every action. "Of course, a block can disappear or reappear, there can be lag, but most of the time it feels very fluid."
