There seem to be a few warring philosophies to the current conversation around d3. One side seems to think that exploits and mechanics should just be left alone, that broken overpoweredness is what it's all about, and the other side of the coin is the people more interested in balance.
Now, I'll start by saying I'm on the side of balance. But there's a reason why we all should be very interested in basic mechanics that are balanced.
The heart of d3 is the skills system. When I first read about how skills will scale in d3, I immediately knew this would be the loot pinata dungeon crawler of all time. This game is essentially an orgasm of math and scalability. The devs basically said.. 'screw it, we're going to throw away anything that corresponds to "sense" and make this game capable of scaling up and down based simpler math'. What does this mean for us?
Each skill can be balanced. Note that I said.. can be.. some skills are clearly superior to others based on factors outside of the numbers on skills. For instance, the demon hunters grenades are ridiculously hard to use solo.. and practically useless against fast enemies because of the casting animation and the time it takes to actually explode (at least in the current meta) The problem with skills like this is that there's probably a very specific build or group composition that can take advantage of the skill, but you need either or to make it worth taking. That's something of a problem but it also gives people a reason to group or swap whole skill sets..
For the sake of fun.. we want to tune all the available skills so that they are worth taking and at the same time.. are soft counters for elite/champ affixes so that we can gear to. Why do we want to do this? For the simple fact that although nephalem valor is completely OP, sometimes that calling for progression is too insistent to quit and restart the run.