IMO - the simplest solutions is a best solutions, like AK-47. For subs common legacy wallet, for others no. Player should be cared to be a sub all time. (if he want). Or Common legacy wallet for all players f2p too, but with credit limit, for subs unlimited.
Bigger legacy cargo - what's problem is with it ? Cartel unlock for more sheets, (for example) max to 10 pcs and go.
Game should give pleasure to player, no torment. If player don't have pleasure with game, don't play.