Interesting discussion you all have had. I looked at the videos of Lochte and Irie and there is a noticeable difference in the amount of rotation each has from the waist down. Lochte is pretty much at 90 deg and Irie is close to 45 deg or a little less. This rotation is what is causing the difference in their kicking. For Lochte the over rotation does not allow for an opposite kick timed with the opposite arm pull. Iris has a good 6 beat kick with the emphasis or power kick coming at the timing of the catch, body rotation and pull. Iris' kick is more like a waltz tempo with a 1,2,3 - 1,2,3 with the 1's being the power kick.
I grew up as mainly a backstroker and IMer due to my back and fly. I don't think I ever gave my kick much thought and not one of my coaches talked to me about it other than kick harder. It wasn't until I learned the 2 beat kick for freestyle 6 years ago that I started to experiment with it in backstroke. I find it easy to use at slow tempos but not at a 50 or 100 pace and switch to more of the traditional 6 beat with emphasis on the 1 kick for each side. Using the 2BK in the slower tempos helped me connect the dots for the emphasis kicks at the faster tempos.
The other interesting thing I discovered was after I started using the Tempo trainer for freestyle I started to play around with it for the other 3 strokes. I found through stroke counting that my backstroke spl was 1-2 higher than my freestyle. What I didn't realize until after I started using the TT was how lazy of a backstroker I was. I first set the TT at my freestyle setting and quickly discovered it was too fast to keep up with and moved it .05 slower. I used the beep for entry and it changed my backstroke to a driven hand entry versus my old lazy entry. I have always had a quick beginning of the recovery just never realized how lazy I was on entry. After a few months moved the tempo back to my freestyle setting and now use the setting. I also use the same setting for breaststroke but divide the stroke in 2 beeps, one for extending to extension and the other beep for brining the hands in under the face and it has sped up by breaststroke as well. The fly was the toughest to figure until recently and am using a setting around .77 - .80 and again a beep for entry and a beep for finish. This also has sped up my hand and timed my kick better for finish and exit.
Very good discussion over the past year.