SC2 requires a constant internet connection and has an interwoven multiplayer component that was supposed to be something akin to an eSport, which would have been a problem if they had not developed solutions for the lag: In multiplayer, if there is a problem with lag, the game slows down and pauses for everyone. Nothing happens while you are lagging and everyone can see who the offending player is.
I don't believe it should be that difficult to bring the same system to Diablo 3, and there shouldn't be a issue with one being an action RPG or an RTS since both require precision timing, far more so than the likes of WoW. If the Blizzard servers can detect lag in one game, there shouldn't be a problem in detecting it in another, especially with disconnects.
So my solution is simply to bring a well developed lag solution from one blizzard game to this one.