(Longer post than it needs to be warning!!!!!!)
Not disagreeing, just saw different stuff I guess.
Every sumo puller I knew way back when, if they died, died at the top (complete failures due to "why did you call for that weight?!" notwithstanding.)
When I judged, sumo-ers were the most notorious shelvers/hitchers.
Most prevalent fail was starting the forward hip thrust with locked knees (knees do not continue to open as hips open.)
You know what I mean?
Ankle angle relative to foot, which started open (read: "vertical shins")or at least was opening (read: "not quite vertical shins at start, but pretty vertical as bar passes knee") now starts to close, knee angle stays (+/-) the same, hips go forward, upper body tries to go vertical but bar has stalled so shoulders round forward, hitching starts, I have thumb pressing RED LIGHT button.
Cue for all deadlifters (read: "here's some crap I made up."): There is a cable attached to the spinous processes on the T1 through T3 vertebrae. It goes straight up into the sky. Magical.
When you start to pull, no matter your style or how you set up, the pull is coming from that cable and it is continuous and stupid fast. It is continuously trying to accelerate you.
Since you are hanging from that cable, your chest WILL not cave, you WILL not go forward nor will you go back. You just fly straight up imaging that cable at that point pulling on you like all hell. That is all you need to think about and react to. Just go as fast and as hard as possible all focused from that point, along that cable. That's all. Fuck the bar, fuck the "cues", fuck the corner of your belt buckle which is trying to remove your appendix (anybody else, or is this just me?), fuck throwing your head back like some overly emotive porn star.
Also, I think (again: "here's some crap I made up") that we are all afraid, as strong folk, to back off a few pounds when we are having a form problem. Instead we start adding all kinds of new accessory exercises to compensate for what we think to be muscle weaknesses in the lift we are trying to fix. And at the same time, continue to poorly perform the lift we are trying to fix.
As luck would have it, deadlifts are both an exercise and an event. Thus, deadlifts can be used to train your deadlift. Deadlift flawlessly a lot, and in time you will become a better and stronger deadlifter.
Back off by 30% (I just made that up), find your center (see above), pull like a motherfucker, stop each set before you fall into poor from (for me, sets of 3 is my marathon limit), do lots and lots of sets, look around to see who in the gym recognizes that you are a beast, acknowledge them with a nearly imperceptible nod, do a few more sets, go home, eat meat. Come back in a week, add some weight, repeat. When it gets dicey, back off a bit and start over.