BOOM! You nailed it! I used to be all about maxing on deads, got to 560lbs and saw a video of myself and realized it was too sloppy. Now I keep it 5plates per side or less, and just go for slow, clean reps. Back has never grown better.
Bingo! Form first, then poundage. The other thing about deadlifts that people don't realize is that there are two phases to the movement.
1. From the floor to your knees, the weight should be moved only with the legs. You are essentially doing the bottom half of a squat.
2. As the bar passes your knees the weight should be progressively shifted to the back, so by the time you are standing erect your back is doing all the work.
The negative is the opposite: your back controls the weight as the bar lowers toward your knees, but once past your knees the legs take over.
For anyone having neck or back pain, I recommend looking up at the ceiling the whole time you are deadlifting (or squatting). This forces your lower back to stay flat and should alleviate any back or neck issues.