The current interaction with Retainers is cumbersome and sluggish. As an additional service that I pay for, it's like the more retainers I pay for the more hassle I have to deal with.

Please revamp the retainer menu. Have the summoning bell summon all your retainers at once so you can move item in and out of inventories between retainers with ease. It's like a group meeting, so you can assign out ventures as a group instead of a one on one basis.

One menu to manage them all would be a very nice quality of life feature.