I am a travel agent who ONLY books Disney. I do know what you all are talking about with being concerned about a TA not checking your vacation for updated discounts, rates, etc... That happened to me before I became a TA! (It was very frustrating, but my trip wasn't booked with a Disney-exclusive TA)
I'm not trying to "get your business" but I am here to tell you what a travel agent does... I book trips and ANY time a new discount comes out, I plug in my client's vacations to see which choice saves them more money. I saved someone almost $1,000 a while back, and I was happy to help them. If you are concerned with a TA saying "Oh, I don't want their trip total to go down because it will decrease my commissions," let me ASSURE you that the small amount of commission I would lose over getting my clients a greater deal is TINY compared to the gratefulness they have for my services. This is how we, as travel agents, get referrals & return customers!
I offer concierge services to all my clients (as do many Disney-exclusive TAs.)
For example, I got up at 5:30am & was on the phone with Disney for 3.5 hours, and made 400+ phone calls to get some of my clients ADRs at "Be Our Guest." And I was HAPPY to do it!
I "get my kicks" making my clients happy, and I'm sure most Disney TAs would say the same!
I give a day-by-day itinerary to each client, along with a bonus for booking with me. Again, this is something most of us offer. But, I can tell you it's not a service you'll find with all TAs, especially those who book regular/non-Disney trips. My clients know they can call me 24 hours a day to ask 1 or 1000 questions. (The Disney phone line is definitely not open 24 hours a day!)
Remember, booking with a TA doesn't cost you one dime. Like Jersey Dad mentioned, yes you can book it yourself. But by booking through a TA, you are helping to employ other Disney fanatics, like yourself!