Re: Monster respawning in D3
In some ways a re-spawning system would be pretty cool.
Imagine a D2 where players could start with killing Andy, move on to a pit run, kill Mephisto, Clear out Chaos and do Diablo, Go to act 5 with Shenk/Eldritch/Pindle, finish off with the Worldstone and Baal.
By the time you're done with Baal, places like Act 1/2/3 have already started re-spawning and you can go back and do those over again. It's kind of a neat idea to think about.
On the other hand, the speed in which a game takes to create, the randomization of the levels and enemies, the complete resetting of an instanced world opposed to a consistent one like in a MMO makes monster re-spawning mostly pointless. Overall it's a lot more interesting to do the full run and once finished, restart with a new game. The levels will be different and give you a fresh take on the run. Things will be different each time which keeps it from being boring.
Re-spawning is a necessity in a consistent world. For an instanced game like Diablo, monster respawning is unnecessary because you can just start a new game and accomplish the same idea.
I think the only upside of re-spawning is the load on Blizzard servers. With monster re-spawn there would be few games created and less strain on the server, but even that isn't a huge decided factor to introduce such a feature. Plus you would lose a little of the immersion if monsters just came back to life after you killed them within the same game. I like the idea of starting a new game with a clean slate.