As the title says. I don't have much, but I imagine others do, so I'll start with a few of my own.
Turbine should never:
- Base raid drop rates with the addition of Raid Timer Bypasses.
- Try to make grinding things too complicated. Seriously, think simple!
- Make items with a save DC on it that doesn't scale up well.
- Go back to the old ways of some things (Death XP penalties, requiring a group for just about everything, hidden recipe crafting BS, exc.)
- Throw away or ignore data that might be useful (I.E.: Why we don't like the present end-game, why some items are or are not effective at various levels, exc.)
- Try to make a single raid contain EVERYTHING in a particular category for every class combination. If you try to please everyone, you'll please noone.
- Sell high-end raid items, various other special items (Including the collapsed portable hole, which sadly has already happened) and collectables for astral shards.