Roller hockey and other sports suffer from the inability of roller blades to fully simulate ice skating motions, due in large part to the inability to use rapid sideways braking.
This rollerblade design would have the following two key modifications:
1) Slightly larger then commonly used today
wheels along the center strip with a cut shape (i.e. forming a V as opposed to a -_- at the contact point with the surface
2) slightly smaller rollers on both sides of the boot that allow unimpeded forward movement, but when rolled laterally have seat belt type stop action.
When doing sideways braking, the foot rests almost entirely on these smaller rollers and the V surface larger wheels just slide along.