I work at a camp in Vermont during the summer that runs a trip to the Rapid River in Maine, and last summer we got an '10 all-star. My buddy who came to meet us there brought his all-star, which i think was an '07, but it might have been an earlier or later model. Regardless, it was definitely that same generation as the '07, and the difference was clear.
Rapid River has a particularly nice hole, called Smooth Ledge, that is pretty predictable and good for most moves, skill dependent, during the weekend releases. At one point my buddy had to leave, without his boat, so I got to try the two back to back for hours at this hole.
I first tried my buddy's '07 all star in '08, in this same hole, and I remember being shocked at how smooth the boat transitioned and spun, likening the experience to "butter on a hot frying pan." However, having spent most of the summer and the trip playing in the '10 all star, it made the previous model feel more sluggish, but also more forgiving. The new all star feels so much shorter, and it flys around like a wild bitch, spinning with the slightest effort and huge pop and release. However, because it is so much looser you have to watch your edges more than the '07, which also felt like a little more weight, which made cartwheels and spins seem more controlled.
We camped at the bottom of the river, below smooth ledge, so I could run S-Turn, which is probably a solid III even though its marked IV, with no problems. The new all star does not have great speed, nor great stability, but it sounds like it would be fine as a replacement for your '07, assuming you're able to keep the '07 upright on III+.
Hope this helps