'Screwing around with light weights' or 'Deload weeks' aren't an essential part of the programme. Jim says this in the book, not essential but recommended if you need a bit of a break.
I'm not sure what you consider to be new about this programme. Not once have I ever heard somebody refer to this progression as new.
Surprisingly however, you don't seem to put much faith in the programme. There's plenty of success(and I think there's even threads dedicated to 5/3/1 gains somewhere on this site) to attest to the programme's effectiveness.
Having said all this however, I feel that the most valuable thing I've gotten from this programme is learning what works for my body. When to pile on the volume and when to ease back, when to take a rest and when to launch hell-for leather into heavy sets across. Like I said, I don't adhere to percentage based training much anymore, I just do what I feel works for me these days.
I suppose that just comes with experience in the weight room though