As they continue to iterate on the D3 design I think that they are getting closer and closer to their true vision of the game so in the next few months I would expect the following exciting changes:
1. Runestones will be removed and changed to "rune etchings". Rune etchings are automatically obtained as you level every 5 levels of so. As soon as available you can inscribe an etching on your spell changing it the way a runestone would have. Of course there is no restriction on swapping out the etching as they are freely interchangeable at all times.
2. All items will be removed from the game except for legendaries, set items and crafting materials which is now a drop. A new interface in your inventory now lists the number of each type of material you have. We found that people really only care about legendaries, set items and crafted items anyway, so removing them allows us better itemize and balance the game, especially boss fights since it is so much more predictable what gear people will be wearing at each boss fight
3. Resistances on gear will be removed. It was found that figuring out what lightning or fire resistance did was too difficult for play testers grandmothers, and in house testers were very frustrated at not having the right type of resistance gear drop before some key bosses. To fix this critical issue, all characters will automatically develop resistances as they level. To provide some interest for bosses and champion monsters, these types of mobs can be imbued with skills that ignore some of your base resistance to a certain type of damage. To balance this, champions and bosses that have special elemental or poison attacks will now drop "resistance orbs" tuned to the type of damage the boss drops. Doing this allows the battle to be very balanced and have interesting mechanics without providing a barrier that requires certain gear, as the "resistance orbs" that temporarily buff resistance to provide a really unique and interesting mechanic for these fights. This power up type of mechanic is viewed as very intuitve by testers and will likely be expanded into other areas
4. Names will be removed as all characters are identified with their Battle Tag so names are no longer needed. A number scheme will be added for multiple characters of a particular type
5. Hardcore mode will be unlocked through a shard of the Worldstone which can only be obtained from killing Diablo on Inferno level. It is a rare legendary drop and only one can drop per group. As inferno DIablo is the ultimate battle he can only be killed in a group of 4. The shard can also be purchased for $19.99 directly from Blizzard on the RMAH
6. Along these lines, it was decided that certain crafting materials and rune etchings have a very significant effect on the playability of the game. As such, these "super" materials and etchings will only be available from Blizzard on the RMAH. Having these be a drop would have provided an unfair advantage to people who can play more so having these key items on the RMAH makes it a much more level playing field for casual Diablo 3 players.
7. Certain special set items will become available on a monthly basis on the RMAH. A portion of the proceeds will go to charitable causes.
8. Advanced tool tips have been removed as they were confusing to players, led to too much theorycrafting and made it too difficult to make balancing changes since the tool tips would have to be updated so much. Only the simple tool tips are now in the game.
9. A compare item feature has been created. Holding down shift when selecting a piece of armor or weapon will automatically display a message stating which item is "better" for your class. All the damage numbers and math was getting a little too confusing for a lot of players. Many beta testers asked for a simple way to know which item was better. We do not want players to have to struggle over these decisions we want to get them back into the action.
10. Battle Net access now costs $5.99 a month. Although we wanted to keep BattleNet free it was determined that we could not provide the type of experience and content we wanted in a free model. We think that $5.99 is a very fair price as we will be bringing out new content quite often both for free (mostly bug fixes) and new content that can be added through the RMAH. All subscribers to the Diablo Battle Net service will receive a free in game mount and pet in WOW.