Anything will work for a while. Try it out for a month or two and see for yourself. Personally, I think it's not 1/10 as good as what you're doing now for your 5x5. Your focus NOW is compounds structured around the squat. Strength gains might be lowered since your frequency is lowered, and doing legs/back only once a week is harsh!
I think Sleazy tried that program and completely plateaued..Even with their remedy of 5 x 3.
I found I never plateaued with planned overtraining and cycling intensity with volume... Which this program doesn't do. This one I imagine would continue for 8 + weeks (some exercises 5x5, some 5x3), then take a week off and pick different exercises and continue.
I guess I'm biased in the end. If doing Bill Starr's 5x5 is bringing continued results, but you're personally a little bored with it, it would make more sense to me to keep the structure, keep the principles, and just tweek exercises/volume/intensity.. Something like doing squat variants, 5-6 sets of singles for an exercise or two, ect....