If you can ease the plane into a stall with the throttle at idle then your CG is fine. A stall doesn't always drop the nose it can just get a steep descent with a nose up attitude. If your engine is idling too high and/or you have a higher pitch smaller prop, that can cause it to not slow down well. The most common problem is most pilots don't slow down enough on final. If you wait for the flare to slow down then it will float down the runway, and you will overshoot. You can only increase the throw so much on the ailerons before you reach a diminishing return. Most true trainers will not ever roll fast and they are rarely axial due to the design, they just are not designed to do most aerobatics well. It would take some design changes to get a faster roll.