Creators need an update

hello me as a map creator and a starer datapack developer noticed that alot of amazing ideas the community has about so many topics just couldnt be done and a lot of them want that changed

one of the problems i phased was trying to create a double chest size gui for my minecraft minigame, a thing that couldnt be done without a plugin or mod but can be done with a normal size chset which works fine but gives so little of  a space to work with

the way i do that is detect whenever the player is holding a specipic item and tell the game to teleport a minecart chest to the player so whenever he right clicks the gui will open the minecart chest but im am limited duo to the fact you cant store a double chest inside a minecart so we can make that you can only get a double minecart in a chest with commands it will look the same as a normal chest minecart but will trigger the double chest gui

ill probably have more things that will be helpfull for map creators like having a world divided to mini servers you can go to like a different dimansion  

thank you if a double chest minecart will get added that will be so helpfull