I think if you made the loom points transferable you'd have to put a limit on it to keep it balanced as it is now.
As an idea, when your main can retire, you put an auction up "Offer: Heirloom +1" and then when somebody buys it, they select one of their items they would like to +1, and the character auto retires with the item in the buyer's possession getting the upgrade.
This way, the system is as it is currently balance-wise, but several steps are removed.
Unless there was a high fee for storing/redeeming loom points off of items I don't think I could get behind that, as you can pick up cheap loom points from alts, and could potentially use those to quickly +3 new and in-demand items.