I feel the same way. We will be staying offsite next trip. The last one with FD at an ASMu suite was too expensive for what we received. I've been going to WDW for years and years and the costs are way up by comparison to other vacations. Just my thoughts of course. A silly comparison that comes to mind. In 1977 we were at WDW for 3 days. The tickets were around $10/day and a room about $40 at one of the DownTown Disney hotels. We went on a 3 day Bahamas cruise from Miami as well on the same trip that cost about $600 for a porthole cabin! Now a 3 day pass is way up as well as those hotels. A 3 day Bahamas cruise can be purchased for $179 at many times with a large window. Just a little comparison as to how cruising has actually come down while WDW really has increased.
For AP holders, when you want to add the dining plan, it becomes a package, you just don't have to buy a ticket with it. You can still get an AP discount on the room part. You can't get an AP dining package with free dining.
If they aren't annual pass holders than I believe that they have to buy park tickets in order to add the dining plan. They can add the dining plan (and tickets, if applicable) up to five days ahead of check in without incurring an extra charge.
Even if you are an AP holder you must convert the room only reservation to a package - albeit a ticketless package. Same goes for military.
The only guests who can get DDP without booking a package of some type are DVC members booking through Member Services.
Guests with a room only reservation who wish to convert it to a package in order to get DDP need to cancel their room only reservation and book a package. If they are not eligible for a ticketless package, they''ll need to buy at least 1 day park tickets (2 days for the free dining promotion) as part of the package. If they're using a discount in most instances they can keep the room discount when they switch to a package. They should ask about that when they call.