Items in question can be easily prevented from being moved along tabs, if that's the problem. Just like going in someone's house and opening their chests. You can view and take unlocked items, but try to do the same with fusion stones.
IMHO, gear, jewels, puries brought for DIAS and house items should be sharable within accoun.
@KatalanOrk - As for prices reduction, if Froggy likes to grow the game, they should make CS more available in game. What would newbie think if you tell them that Free 2 Play game - to T10 weapon you need 3.5K DIAS. And that is with current sale of 1 for 1. EU servers have population that we can just hope to have.