Sure every block with Inventory would work. But with the new /spactate command a similar command has been added, so here is my idea for this command:
/spactate entity <target> <player>
like the command works yet
/spactate block <x y z> <player>
opens the inventory of a chest, should also be possible if you aren't in spcator mode to change the items.
/spactate inventory <target> <player>
opens the inventory of the target entity, like player or villager
/spactate enderchest <target> <player>
opens the enderchest of the target player
What do you think about this?