Both feet flat on the floor when sliding forward and sideways?

You could be flat footed and take smaller steps but it isn't practical nor effective.

 

Everything changed in 67 Rubber Soles

 

The sense of Feel changed

 

No.
Sounds like he is dumb as a stump.

 

My coach would be all over you if you had your feet flat, and he's been coaching over 40 years and was a former pro.

He says that if you are on your heels and you get hit, there is nowhere for the velocity to transfer to and you wind up off balance and on your ass.

Also, the power in your punches comes from pivoting your weight, which you can't do as well with your back foot flat.

At the moment I do six rounds of footwork drills each session, facing the mirror to make sure my back heel is up, and my balance is perfect.

 

You might find yourself striding, if you keep both feet flat. Alternatively, you might find yourself taking tiny steps, very quickly and getting nowhere. I too keep my leading foot flat and rear heel slightly raised. But, my weight is concentrated in the balls of both feet, so as to 'push' off the ground as necessary.

 

Doesnt make sense to me either, how are you going to move any direction competently with your back heel flat?