So I have just returned to the game after about 15 months off. During my time off from DDO I played quite a bit of Guild Wars 2 and although I was not as impressed with GW2 as much as I had hoped, it definitely had some very positive design aspects.
So, based on my experiences both DDO and GW2, I have a couple of suggestions:
1. Get rid of character based mailboxes. Link the mail box to the player's account (accessible from any character). It would be nice if you could still mail to yourself. I hate logging on thinking "I've got mail!" only to find it's the same **** I read on 6 other characters already.
2. Add an account based Collectible/Ingredient page to the inventory page. Or maybe implement a whole new interface (like the monster manual(s)). Either way, collectibles and ingredients that are not BtC should not have to be micromanaged back and forth across characters, it is pointless time-wasting.
BtC, BtA and non-bound items should be accessible from this GUI. The design should lend itself to meeting player needs For example: What does my collection of shards/scrolls/seals look like, at a glance.
Ingredients bags are just a searchable backpack that I can't organise very easily.
3. Get rid of the character based purse. Create an account based one with plat limits of (current character based plat cap)*(number of character slots available on account).
4. A natural consequence of the above changes will be an account based Auction house system.
5. Get rid of spell components. They are...silly. Put a quest chain or some reputation reward to earn the "From thin Air" title or something and make people earn a "no-components" ability if it makes you happy.
Just a few suggestions. Probably not high on everyone's list, but I have always felt that the inventory management aspect DDO left a LOT to be desired.