I absolutely know what you mean! I actually used to be a
travel agent myself a few years ago, and Disney was my specialty. So, I usually do know more about Disney between being a travel agent, going to Disney many many times, and just being a Disney fanatic!
Anyway, I have used AAA for the past 4 trips because I was able to save a few hundred dollars, so it is worth it for us. Luckily, I found a great TA to work with. She is very reliable, and even though I do know more about Disney than she does, she acutally gets a kick out of it....and it makes her job much easier!
I beleive it all depends on the TA that you have. Some may love the fact that you are basically doing most of the leg work, other than the booking aspects, but others may think otherwise.
If you do happen to encounter a less than friendly TA, then I wouldn't deal with them, find another. Like I said, usually they would be happy for the fact that you are making their job easier!
For the poster who asked about ADRs: Yes, you can make your own, I always do. If you did want your TA to, they could...but you can absolutely make your own as well.