Tail heavy is never a good condition. Some 3D flyers have the CG at the aft end of the recommended range, but this doesn't constitute a tail heavy condition. A properly balanced plane (neutral) will be very sensitive to elevator input, which can make landings harder to control. Also the plane may not clearly tell you when the wing is stalled, and the plane may enter a spin when it tip stalls first. A slightly nose heavy plane will tend to drop the nose in a stall and increase airspeed which is a good thing. Yes you will have to hold a small amount of up elevator to keep the nose pitched up, but that is also a good thing.

I train my students to get the plane in a position where its slightly nose up (with elevator) and descending (establish that attitude when the plane is on the base leg. This puts the plane in the perfect attitude for touchdown, and prevents bouncing, particularly with tricycle gear planes. They then control the altitude with throttle, and the speed with elevator. If you want to slow the plane down, add more elevator. If you want to pull the plane up to the glide path, add some throttle.

Brad