Agree. On S and M class it’s not an issue because the MDR kitchen is located with the Luminae kitchen.
On E class, the kitchens are at opposite ends of the ship. Generally, you can’t order off those menus the day of. I’ve seen the odd post on here where folks who say they have, but in my opinion, it’s not fair to make the servers run to the other end of the ship. They will do their best to accommodate you if you give them a day’s notice though.
As for delivering to your suite, room type matters. Luminae is not available to be delivered to your room. Just the regular main dining room. Sometimes the PH or other top suite can get it delivered, but that’s it.