I wasn't meaning you directly with all of my comments when responding to your question. I took that opportunity to address other issues. There seems to be a growing trend around here of being argumentative for fashion and not function.
I'm not fully understanding the question. Being bladed helps to face the center line, but it's not mandatory exactly. I don't know of any fighters who fight EXACTLY square and do well, so when anyone gets an angle to their stance at all, facing the center line in the manner referenced here is pretty elementary. A lot of fighters do it by accident, then have trouble maintaining it.
There are very subtle ways of procuring angles from right in front of a fighter without moving to either side of their center. it's just very difficult. But I'll give you a hing, Broner did it A LOT to DeMarco in their bout.
Ali's footwork was only flimsy by comparison to smaller fighters. For a heavyweight it was exceptional. However when you take the guys he was emulating...Rodriguez, Napoles, Pastrano, Dupas, he definitely seems flimsy. As far as lead hooks, that's relative to whether or not it's the person's power hand (and by hand I mean facilitated by hip-rotation) or not. For instance, I'd much rather get hit by Carlos Monzon's left hook than his right hand.
I'm not sure what you're having trouble seeing. From the onset, Senchai has his lead toe aimed directly at Pinca's center, and he works from there. It's evident within the first 30 seconds of that video. Every time he steps directly in towards Pinca that way (without doing anything fancy) Pinca has a hard time keeping him off and is forced to disengage. Pinca becomes reactive and panicky when advanced upon. Perhaps panicky is a strong word, but sensitive. When Pinca tries to attack, his lead foot is way outside of Senchai's, but it doesn't serve him well. It effectively neutralizes his left side and gives him ONLY his right side to attack with effectively (without moving too much). It puts him in a position of having to try to hit Senchai with the furthest available weapon, and without putting him in position to be hit by it in the first place.
Mind-you, this doesn't always directly change the outcome of a fight, there are ways people can and have overcome this principal. But when used correctly, it's a very strong thing to have in place.