They should just release a large amount of SG items that rotate every 3 months and add the limited time/seasonal/holiday outfit bundle sets every 2 weeks. That way more and more new players coming into the game can still have a chance to either farm SG or buy SG with real money. Also having a "wish-list" button allows people who missed the SG items to maybe get it in a future rotation.
I dont think SG items should be tradable because it will affect the AC/meseta market aswell and also decrease the FOMO since you can just sell AC items or BOTS farming meseta, i would like to keep them seperated and view SG items as more of a indulgent luxury.
I agree you should be able to purchase the SG items twice for global account use since it helps deplete our SG and makes the purchase decision more important. I think SG tickets should decrease in price to 50 SG per roll because they put a bunch of useless filler in an already RNG scratch vs some solid items we already get in FF.