I'd also like to vote for a 'share all quests upon acceptance' option whereby the main toon automatically shares new quests as they are accepted. I sometimes run with mixed teams, and it's not always clear who has done what quest. With the quest-related achievements now in the game, I'm also going back to pick up gray quests, with mixed participation among my alts.

I love the inventory management ideas mentioned a couple pages ago. In it's simplest form, auto-trading junk, potions, and cooking items to alts who have room would be a really nice time saver. A more advanced version might trade all cloth to a particular alt, all gems to the enchanting alt etc but programming that is probably more trouble than it's worth.

edit: update - looks like Tynk linked to some quest sharing code in this thread: Slave quest