this video is great, i've watched it quite a few times in the past. no question these guys have big hip slide, and it's a power move for sure. but they use it also for timing, ie: if they are early on a pitch, more hip slide; late on a pitch, less hip slide.
for what it's worth, pitchers use a huge hip slide also.
lindsey's point is true too, this footage doesn't tell much about whether or not a hip slide hinders the ultra-precise move of repetitive squaring of the clubface.
also, almost all these guys fall back onto their back foot near the end of the motion. this would seem to be less detrimental with an uppercut swing on a ball near waist level vs. a golf ball on or near the ground.
I wonder if anybody in the long drive world has tried to hit like a baseball player lifting their front leg of the ground and restepping into it? Other than Paddy imitating happy Gilmore.
that's an interesting point. my gut feeling is that there is power in that move. i mean, think about it, these guys have to react to a 98 MPH fastball (in a normal game) and they're STILL taking that step. if it was unnecessary, they could ditch it and have a lot more time to react to the ball.
there's a run-up in all the field sports i can think of also. (javelin, discus, shot put, hammer)