That's a pretty slick idea. The replaceable abrasive part is about $2 cheaper than the old 1-piece style. For changing between steel, aluminum and stainless abrasives it'd be a lot more convenient.
Klingspor needs to do a better job in outlining what each abrasive wheel is recommended for. As of now, they offer 3 different wheels in the same diameter, with the same grit and using the same Alumina Zirconia abrasive material with no mention as to what each wheel should be used on. [sad]