Just my thoughts.. take them or leave them :)
Any experience I have ever had with room service...
It is common practice for the customer to place their used dishes in the hallway, and it is common practice for hotels to request you to do this (land or sea).
Of course there is always going to be different ways to do things that we don't all agree with or understand, this will not change now or ever.
Call, leave them outside your door, carry them back... go with the system or go against the system... whatever you do be as courteous as you can to those around you and have fun! Sometimes you just have to do you.
Worrying about the small stuff will just be a source of unnecessary stress that could ruin a moment, a day, or an entire vacation.
As far as the bags go... my preference would definitely be that they were at least available. Alternatively it can be delivered to your cabin and most of us have some sort of small bag or backpack that goes with on excursions, so would not be bringing along anything additional on my cruise.
But hey... again.... small stuff
Do your thing and have fun doing it!