AAA usually has what is almost a year round discount that their members can get when you book a room. This doesn't need to be done through AAA, simply asking for the AAA member discount when calling CRO is sufficient. However, this is usually only 5-10% off, well below what the other discounts end up being. However, if it is a popular room category or time, there may not be other discounts available.
The other things mentioned are kinda meh in my opinion, and typically require you to book with AAA directly. The "Diamond" parking isn't terrible, but some of the parks there is other closer parking, and if you aren't driving to the parks, its a non issue. At times they do offer special character M&G's or the like, but I have no idea if they are offering any right now. I don't know if any of them are worth it. Many of the AAA TAs are general knowledge TAs, and have as much WDW knowledge as they do about Rome or London. So they may not know how important it is to call for CRT at 180+10, and usually won't try to rebook your trip to take advantage of any other/better discounts that may get released.
That said, I am a AAA member and have been since I got my license. The other discounts are usually helpful, and I have recouped my membership costs through a few tows, jumps, and car unlockings.