Blizzard has stated that they intend on addressing balance in Inferno difficulty. In particular they talked about how damage in Inferno was supposed to be a drain on your health and how mitigating that drain was a really important point. They want to reduce damage spikiness in Inferno in the coming patch.
What exactly do they mean by *spikiness*?
Everything in later Inferno 1 shots me on my Witch Doctor aside from weak aoe attacks like Electrified bolts, a tick or two of Desecration or junk mob melee attacks. Generally those things that don't 1 shot me kill me in 2 hits instead though so there is virtually no forgiveness. The thing is though that there is no spikiness anywhere. *Everything* hits that hard. I would describe damage as spiky if I was able to take lots of hits from monsters but occasionally be 1 shotted by a particular effect - that effect is probably out of line. In this case though the damage isn't spiky, it is just really, really high.
Another issue is the way in which various classes deal with damage. On my Witch Doctor I have 20% damage reduction and a ton of Int which means I take about 30% less damage than a similarly geared Demon Hunter. The WD still gets 1 shotted regularly though and that is even with him stacking defensive stats really, really hard. It isn't even possible for my DH to stack enough defenses to live through a hit because I would need to gear like the WD, overcome a 30%!!! deficit and then *still* get 1 shotted. Given that I do what everyone else does which is gear purely for offense and accept that I die to any hit that lands. It is no problem to progress through the game under the assumption that any hit kills me and gearing to survive multiple hits in a row is effectively impossible so everybody plays a pure glass cannon. This is exacerbated by the fact that the DH gets a lot of Dodge from stacking Dex so I already avoid many attacks flat out. My best strategy is to kill the enemies before I run out of room to kite or cooldowns to hit.
I am not complaining about Inferno being too hard. In fact I think it is good that it is hard and it is entirely possible for everyone to progress through it with a lot of farming - you might well think that the amount of farming is too high but time is the only barrier. Note that melee have it much worse than ranged in terms of gear requirements and I don't like that much but I don't see a good way around it either. There has always been a huge problem balancing melee and ranged in twitch games and D3 is no exception.
There are some real problems in the game that I hope are addressed in the next patch. I have not played a Monk or Wizard yet so I will mostly leave those alone but I have high level characters of the other three classes and there are some things that need looking at.
Witch Doctor: Mana is a disaster. If the WD had much better base regen they could actually use their spells in some way that made sense. Zombie Bears would be horribly overpowered if they could be spammed without using Vision Quest though so they would likely need a nerf. Pets aren't particularly functional either because they just die instantly to any monster. Making them nearly invincible introduces all kinds of other problems but I have a potential solution: Remove the cooldowns on the pets. They would die constantly but they could be brought back if the WD is willing to spend the time and mana to do so. This would mean that a summoner could maintain a packs of dorks but there would be a real cost to doing so - I would imagine that is a much better situation then now where they are a wasted slot on your bar.
Demon Hunter: Nether Tentacles is absurdly overpowered. It does outrageous damage in both AOE and single target settings, far more damage than anything any other class has available. It needs a punishing nerf and the most likely way to do so is to give it the AOE damage penalty that other similar skills like Ball Lightning have. At that point it would be comparable to other classes' abilities. This single ability is mostly responsible for DH damage being so much higher than anyone else's.
Barbarian: Rage is not working right. The rage spenders are simply so underwhelming in comparison to the generators that it is far better to never spend rage aside from 2 minute cooldowns. The passive that gives you 25% more damage when at max rage cements this in place. To my mind using that passive should be a niche choice, something people do when they choose not to use rage for some strange reason - a way to make up for avoiding rage spenders. When the standard and optimal build for the class is to completely ignore the resource the class uses something is wrong.
There are of course lots of other less pressing issues. Every class has tons of abilities that are hopelessly bad but I don't know how pressing that is as long as two main things hold: First, that every class feels right and people's intuitive ideas about how they should work are mechanically supported. Barbarians should spend rage, WD should be able to cast their spells, and WD pets should be functional. Second there should be a variety of ways to build a top tier character. There are bad ways to build a character (Angry Chicken!) but as long as there are a number of good ways I will enjoy trying them all out and people will have fun arguing over which is best.