There is no article discussion threads anymore, so I'll start something here.
I think this article was a very good one. TC Luoma is right on the point. It lit something in my head.
Walking lunges has always been the nastiest exercise for me, and I am pretty sure it is for everyone. One real set on walking lunges with heavy DB for max reps leaves you devastated. 3 sets at most and you are done. The chances of injuries are also way lower than in a squat or a deadlift. I always felt my lower body much more doing it than with doina squat or deadlift.
For years I only did them for a period of time, then at some point I would swap them out for something else. In my head it just wasn't mandatory like the squat and the deadlift, probably because of the general training culture with emphasis on powerlifting movements. Not much people do them (for bad reasons I think now). I wish I listened to my instinct instead.
The walking lunge is probably the best exercise indeed. I think it should be one of the first metric of strength and that powerlifting has had too much influence on the gym culture. It's a shame. Every women would be walking with a great ass if it was more mainstream (and every men too, but I wouldn't be able to tell in that case). No exercise can do that on its own like the walking lunge.
Low rep squats don't build that much muscle. High reps can be dangerous when your posture deteriorates and don't build muscle in everyone either. Leg press, romanian deadlifts are good but can't stand on their own. Bulgarian split squats are gimmicky, it's hard to set up and you lose your balance. With any of these you can't trash your lower body effectively in a straightforward manner like with the walking lunge.
I think the problem could be fitting them in your routine. I think the front squat, leg press, straight leg or romanian dl and back squat are mandatory in a week. For 1 leg day in a week there is not much space left. Personally I do all of them on a day with a simple ramp up and I am fatigued. I'll try adding the walking lunge as a next to last exercise with a great emphasis (with the last exercise being either squat or front squat on the back burner, the other one being the main first exercise) for now.