Most Wing Chun schools do a lot of stance pivoting – commonly called ‘shifting’ or ‘turning’ – and this is usually done in Wing Chun to rotate the body without transplanting (only rotating) your planted feet.
On the downside, this creates a very sagittally weak structure. Aikido students are commonly taught to pull your arm to the side, to put you in this same sagittally weak stance so they can then easily push you over, when learning techniques like Tenchi Nage for example.
Some older systems of Wing Chun emphasise adjusting the foot placement after rotating the body, for example by swinging the unweighted foot behind, to create a sagittally strong linear stance whenever it suits the hand technique. The same strong stances are absolute fundamentals in practically all martial arts, from Tai Chi to Karate to Ninjutsu to Capoeira. The rotated body with quicksand feet, however, is a feature only common to Wing Chun. There may be a practical reason for this, but it’s also got obvious shortcomings. Even in the world of gloved-up boxing, Oleksandr Usyk (undefeated, undisputed cruiserweight and heavyweight champion) loves swinging his back foot behind when shifting stances – he does it very sharply & fluidly. I can coach you in the same kind of footwork – of course I’m no Usyk, but I can coach you in the basic principles of this method of pivoting, as someone who’s been doing it instinctively for a long time without ever formally studying it. This is often the case with free-thinking martial artists – we often ‘invent’ certain techniques only to later discover that they’re commonly trained in certain traditional arts or by certain modern martial artists that we weren’t previously so familiar with.
Bruce Lee made similar adjustments himself. Since leaving Hong Kong at the age of 18, he’s never been filmed or pictured doing Ip Man style pivoting as far as I know – he always had at least a slightly bladed stance when doing classic pivoting moves, as can be seen in his posthumously published book series entitled Bruce Lee’s Fighting Method (which he didn’t want released). Even in Chi Sau, he preferred to keep a bladed stance – this is not something I do myself, but when it comes to pronounced pivoting techniques I always try to blade-off my stance for sagittal integrity. Note that this same swinging back of the unweighted leg forms the basis of Capoeira’s most important & iconic footwork drill – the Ginga. Now I’m no Capoeirista, but ‘real recognise real’ as the kids say.