More specifically MDK is the school I would like to start training at. My current Hapkido instructor, i just dont feel that I am learning very well. He seems to only pay attention to the same 3 students every class, the rest of us are just human dummies for them to practice on. THe only time I really learn anything is when we pair up on work serperately in small groups. Enough of my whining though, a buddy at work took is an 3rd Dan at MDK and the school he went to is local. I like Hapkido, but there isnt any other dojangs that are local. I'm thinking i'll find the shift to be pretty easy, I'm only a 7th Gup in HKD.
There will certainly be new techniques and forms to learn. I wouldn't recommend staying where you are, if it is as you describe it to be. They should help all students equally.
You will find that the focus shifts from more joint locking and throws to a more karate based system with an extra kick emphasis (generally). From all that throwing, your hips are probably getting pretty strong - TSD is all about the hips so you will get to learn how to use them in a different way.
At your level, the change won't be as painful to be certain. The techniques are longer because the figting range is greater. There is more power focus on each technique, and the stances will be deeper.