Okay basically Quality of Life ideas are those that are not game breaking, bugs, broken, or fixes. These would be enhancements to the game that would probably most likely take place in spare developer time (ha!)
So to start with some of the common things:
A search feature in the Auction House in addition to the level filter and buyout only options
A way to auto-sort our inventory by level, value, or type of item.
Teleports to Meridia
Those are just a few I can think of at the moment that I'd like to see "worked on" at some point.
Lockable Inventory Space
Inventory and Bank item log export feature
Show crit range on weapon inspection instead of just inventory panel
RSS Auction House Feed
Auto-Follow, Auction History, and a few new timer/clock slash commands
Ability to Export the combat log / parse data
Ability to lock an entire pack in your inventory
In game web-browser and character planner
Transferable UI layout from character to character + others
House Buff UI Change Request (Buy all!)
Scaling Hotbars
Shared Bank Slots
Game Wide Communications
Mentor / Side Kick Feature
Character Sheet Export
Better Info for the Party list
Auction Channel (Non Auction House)
Color WF health bars different, Auto-use skills (open lock / disable) on double click
More detail party window / Ability to combine low charge wands
Fix Anon & Dark Sky
Unlock 32 Point builds @ account level instead of server level when hitting 1750
Sharing Quests
Unique sounds for criticals
Move party members up or down in the party window
Add friends as an incoming text type and Custom Spam filter