Not to bash but I thought his ukemi was some of the crappiest I have seen. I'll grant you that he was very athletic, but that was the end. He was trying to make the thows look big by taking leaping jumps for his ukemi, he also "splayed" out during a lot of his falls, ie spinning horizontally instead of vertically.
I agree with the general sentiment, really emphasize the slap out ukemi from front rolls, once that is ingrained start throwing in such a way that you can control where the hand is in relation to the ground.
Sumi otoshi works pretty well for this. Cheers.