+1 vote even if it uses CC's, if its like the cargo bay, you can craft from it and put in bound items then even better.
Having to mail everything makes it feel like a ten year old game.
Who is going to play an offline rpg without voice , 2d rpg or games with only one save slot?
Games have evolved since.
there are dozens of easy ways to give people legacy cargo the only reason why they wouldn't is if they think they will lose money because people will craft more and not buy equipment from the cartel market or from paying the staff to do it etc. if one way is too expensive than find another way to do it.
you can have a HUD button active when in the cantina, extra npc, addon to the cargo, turn the cargo INTO Legacy and mail all the old items back into your account, have an option to convert an empty cargo tab INTO Legacy etc.