I also noticed recently that the points generation stuff (used for rendering circles and collision of arbitrary polygon) essentially makes circles impossible to use for collision - since every time you move the circle (to coincide with the entity thats moving) all the points are regenerated. It's the first time I've seen a GC performance in 3 years.
The points aren't used for collision checking. They are only used for rendering. The old Circle collision checking code is still there. Circle on Circle and Rectangle on Circle are still streamlined for collisions checking. But those classes on any of the newer ones will do more complex collision checking. The reason the points are regenerated every time is because it was requested in this thread: http://slick.javaunlimited.net/viewtopic.php?t=462
I am not sure what you want to do about this. The main reason for this way of doing things is the Transform class. If you want to remove complex transformations and implement simple scale, rotate and translate into the shape classes, it might make things more manageable.