This isn't going to be another of your usual "diablo 3" sucks (as i think this game is awesome), and it isn't going to be another "barbs are OP" even though they are.

This thread is going to be about options the developer team has had over the half year since the game has been out, and what wrong choices they made. My intention in this post is not to start a typical cry thread, but a real discussion that Blizzard can read AND learn from in order to make this game better for us all.

So after the long introduction i'll get on with what I have to say.

1. Economy - The fact that there even is an AH is GREAT, truly a good idea, because if there was none - a black market would rise, which would make the same problems only less controlled.
The problem with this is that once you have given out a gold AH and RMAH (which is a whole bigger story), you need to understand now that this isn't a normal "pc game" but it is now a fully operating Economy.
That being said here are the problems:

• Gold sinks - There is none. Each patch the game becomes easier, hence less people need to repair items, and more than that every patch the repair prices are lowered.
• Duping - Once you release the AH duping is annoying, that's true. But once you release RMAH duping is a felony. If I buy from RMAH a $250 bow and then dupe it once, i actually created $250 out of thin air (no work at all). [not to mention there are even gold duping videos running over youtube from way back in patch 1.0.3]

How to fix this you ask?

• Gold sinks - Gem upgrading has a fail rate which will make you lose the whole gem, so when you do get to a radiant star it will mean something and there will be little of those, and not trillions like in the market atm.
• Duping - If it has been proved that someone has been hacked and a rollback has been initialized - the account that so called "hacked" him should be blocked OR at a minimum rolled back also

2. Game content.
The biggest problem with the current game is that there is no endgame content, meaning that once a character has finished the game (killed diablo) there is pretty much nothing left to do.
Sure the real hardcore players look for the thrill of being the BEST and will have the proper motivation to be able to finish MP10 and get to Paragon 100, but for the main player mass - this isn't interesting. We want something real, a proper challenge, not finish ACT 3 for the 1000000th time just with each enemy having +10% dps and 150% hp - that's damn boring.

The last patch 1.0.5 brought in the Infernal Machine, a very interesting idea.
People spent days farming for keys and trying to get organs in order to achieve the perfect ring, this made people spend more gold, the inflation went down a tad and now that people have got a good ring - they don't need another, the whole infernal machine has now become as useless as whimsyshire.

3. Class equality.
We all know that the classes aren't equal. I don't want to add anything here as it's obvious what the problems are, just go read another QQ thread on barbs / hunters being so strong, or see how a 50mil barb can stand in unlimited amount of monsters + elites in MP 10 and stay full health without moving or attacking at all.

My point
Listen to the community, the people here bring up great ideas. ideas that you (Blizzard devs) should give more attention to.
For instance what's up with this ring thing? It is pretty useless.. If it was better it would be BiS (like you made the http://us.battle.net/d3/en/item/triumvirate which gives 18% damage bonus even before we start looking at the other affix) and as it is now.. not really worth the hassle - Instead, once you have the whole machine worked up.. got the 3 organs... you now have an option to go to the blacksmith and upgrade an item of your choice, YES upgrade. You give the item of your choice to the blacksmith and he will upgrade one affix giving it a 10% bonus.
Each time you upgrade an item it will get a little blue (1) next to it [next will be (2) then (3).. you got the point]. Each time you take that item for another upgrade it will have a 10*UpgradeLVL chance to fail.
Meaning first time 0% fail chance, 6th time will be 50% chance.
Upon fail - item is gone, item inflation is down, and there is a real challenge in finishing the whole business.

Instead of trying to make a market reset with every patch, when you introduce new rings and amulets / new legendaries, try and make the game balance itself.

http://www.d3rmt.com/auction-house/gold/eu/
This site shows that status of the Gold to Euro, pretty clear that many people are leaving the game and the gold and item inflation is huge while no real gold sink exists.