You don't do cookie cutter. You simply build the counter strategy to the optimum one and then you'll see some variety here. They counter your counter, then counter back. The point is the game changes in that players adapt to each other. Diablo is simply walk into a room, slash it until it dies. There's no strategy.
But Diablo is as simple as walking around and spamming frost nova. There's no physical skill and no higher strategy than that. All one needs is to dedicate large sums of time doing the same repetitive tasks in order to get ahead.
I can name a bunch of games off the top of my head that play just like that: Gauntlet Legends, Phantasy Star Online, Spartan Total Warrior, Dynasty Warriors, Norrath, God of War...
I find PvE in any game boring, well except Pokemon the Trading Card game because the CPU actually plays differently. PvP wise, I think we can all agree Diablo 2 was a joke, so improving on it won't be hard.
So again, all I see is roaming around and killing anything other than yourself. It's a game devoid of any strategy or skill... just whoever can farm the best items. Well if you are a fan of doing this I suppose you'll be in Diablo 3 heaven. I can't imagine playing something this repetitive for more than a few minutes.