I think at all of our TS restaurants, they took the appetizer order first, then came back for entree and dessert together. I figured the reason they asked for your dessert order at that time was, since you're on the plan there's a very good chance you ARE going to order dessert, and you've already got the menu there in front of you.
If someone is not on the plan, they might be more likely to wait until after their entree to decide whether to get dessert or not. Then, they'd have to bring a dessert menu out and wait for you to look it over and decide.
I never felt rushed, and it never occurred to me that I was being slighted or somehow given inferior service because they took our dessert order while we had the menu right there in front of us. If you know you're getting dessert, and you know what you want (and don't pretend we haven't all studied the menus for 3 months and know EXACTLY what we're getting!!) why not order it then? And if you really haven't decided, I'm sure they'd have no problem at all bringing a menu back out after your entree is finished. Even though we ordered dessert at the same time as our entree, the servers always asked "are you ready for me to bring dessert out?" so it's not like they just shoved it in front of us.
... No need to take offense at what is almost certainly an issue of practicality.