I don't know about you guys, but I'm crazy about alts. This means I'm constantly sending my heirloom gear from my druid, to my mage, to my warlock, to my priest, etc etc. This takes a lot of time with all the mailing, and remembering who has what items in their bags.
If you roll a character on a new server, you can't use your heirloom gear. You can't send mail between servers, presumably for economic / scam reasons. This gave me an interesting idea.
There should be a UI feature, similar to the Equipment Manager, which holds your Heirloom gear. You can equip it on any of your alts at any time, without mailing. This way you could level a character on a new server, and use your Heirlooms at the same time.
What do you think? I heard blizzard is doing something similar for tabards in Cataclysm, so this shouldn't be much of a stretch as far as programming goes.