Broaden the set of skills in use by adjusting ALL underused skills upward in power. Repeat until there are no skills/runes under 1/4% utilization.
(I could also add that some skills should only have their own skill powers and dmg not related to weapon DPS)
Give players greater control over their destiny. More and more controlled crafting, socket quest, runes, items that enhance a broader range of specific skills, etc.
(Not only this, but +%elemental dmg on items can't compete with the usual trifectas or even bifectas, +5% fire is no where close to 6% crit chance)
Rarely drop higher level gems so that reaching marquise without the support of gem farmers is realistically possible.
(I tend to agree that even perfect star gems should drop with the exception of marquise, at a very low rate)
Make achievements meaningful (maybe add % of achievements complete to MF, or as a bonus to damage, that sort of thing).
(I'm not sure about this one to add MF or DMG bonus, but a little gift like fun in-game items could be nice, even if its festive items, or a skin to add on an item for example)
Add more content. More side quests, with deeper (possibly infinite) dungeons.
(been talked already, nice idea, although i'm more of a tower type guy, maybe something like Diablo 1 16 floors and have us fight clones of each Lords, from andariel to prime evil)
Remove the BOA of crafted archon items. (This would fix a number of problems currently plaguing the AH). Instead, BOA all items after first sale (to eliminate market cornering behavior).
(I think the crafting of BOA is just plain bad myself, BOA does not have its place in D3)
(Cooldown on potions, and skills should be lowered a lot if not just removed, I can understand for archon or wotb and skills like that.. but for the rest NAH)
Itemization is supposedly on the way, so no point in saying everything that could be done before we actually see what is really planned with lots of details.
Movement speed seems to be an issue people are having, I personnaly hate the fact that I can't run as fast as light using frenzy how it used to be in D2, but maybe its because acts are smaller idk.
Socketing is also something people seems to want back, being able to socket an item ourself even if not repeatable is nice. I also expect to have multisockets weapon (1-6) like D2 and lower the power of gems all together.
I think the MF cap should be removed, who cares if we have 1000% MF, thats what diablo is all about. farming! If we want to be a bit weaker to have higher MF so be it. Right now MF gear is losing value because lots of people are getting closed to paragon 100 anyways.
Release the itemization update sooner rather than later
Expand the game in general. More enemies, areas to explore, gems, legendaries, set items, ect. Make those legendaries and set items give us things like you gain 10% extra damage while at full health and you can have 2 hydras at once or you gain +50% shrine effect and duration.
Give elites and champions a more distinguishing appearance and/or glow.
Fix AH to be able to search all parameters for all available items. IE Be able to search Stone of Jordan with Zombie Bear reduced cost.
Bring back Ethereal items if we are to use indestructible affix
Option to have skip cinematics toggled.
Fix Waller affix so it cant spawn literally on your face.
Option to be able to sell items in auction house for less than the automatic 1day 12hours. Some want to be able to do 6h auction for example.
Release 2 new game modes Hardcore - No Auction House and Softcore - No Auction House.
Ability to travel between acts (even if doing so resets your NV)
Give us a way modify gear of alts without logging into them individually. Example: Above the shared stash are 10 tabs for each alt. You can select the character in question and add/remove gear accordingly.
Provide a means auto-sell/auto-salvage while out in the field. We've seen this done effectively in other games enough to know it would be a benefit.
Let players exceed the 10 item limit in AH with a gold sink penalty that increases as you continue to surpass the limit.
We should have 9 power slots which can be used for any combination of passives/skills (or the F1-12 keys)
increase legendary plan drop rates and set item drop rates. Promoting self-found play means making all aspects of the game available to the larger market of players.
Enhance complexity of followers in terms of gear slots, powers and effectiveness. This will make solo-play a little more enticing which is good after the 1.0.8 multiplayer buff.
Many of us would prefer followers along the lines of Diablo 2 support rather than Diablo 3's minor buff and stat boosting sponges.
Give elemental attack types more meaning. Cold slows, lightning chance to stun, fire chance to spread to adjacent foes for minor DoT, poison chance to deal higher end DoT, etc.