If you have a closed stance, your front foot automatically lands a bit too far across, blocking the bat's quickest path to the ball. In this case, Bailey is forced to go around his front pad somewhat to make contact
Why is it that the ball that pitches outside leg isn't considered a legitimate delivery to get an lbw dismissal?
The moment the ball pitches outside leg, everything else becomes irrelevant, including the batsman not offering a shot and the ball's likelihood of hitting the middle of middle stump.
The reason the batsman gets such a huge favour is that since cricket is a side-on game, there's a blind spot outside leg. Once the batsman stands with his front shoulder pointing towards the bowler, there's bound to be some area outside his leg stump that's not properly visible to him, which is why he's allowed to cover his stumps and let balls pitching in that area hit the pads without offering a shot. This is relevant especially when the bowler goes round the stumps, for the angle ensures that even balls that pitch outside leg end up within the stumps.
To counter this angle, and the blind spot, batsmen are advised to shelve the diktat about cricket being a side-on game and open their stance, right from the toes to the shoulders. By doing this the batsman is able to see the bowler and the ball better - a routine practice while facing left-arm fast bowlers bowling over the stumps.
One man - George Bailey - seems to be attempting to turn this theory on its head. He is not only standing fully side-on but is doing so to an extent where the front leg is not in line with the back leg as it lines up with the stumps, but a little further over to the off side, which makes his stance almost too closed.
Bailey's logic is that his new stance provides him more stability and a better shape while going for the big shots. He started batting with this stance towards the end of last year's IPL. Since then his numbers, in international cricket and the BBL, have improved.
Before the IPL, Bailey had a slightly open stance - the front leg was slightly behind the line of the back leg, even to right-arm bowlers bowling over the stumps.
There's a possibility that if you open up your stance in order to play big shots, your front leg will get planted a little too far away from the back leg, leading the body to fall away at the time of impact and after. The other, more pertinent, problem, as I saw it, was his tendency to get caught behind, because the front foot did not go far enough across for him to get close to the ball. It isn't surprising that the cover drive wasn't his preferred shot.
With the new stance, Bailey's front foot is likely to go a lot more further across and take him closer to the ball, which will lead to fewer nicks. And since the front leg will not open as much as it used to, he is likely to have a more stable base when going for the big shots.
So is it a good idea for other batsmen to adopt Bailey's new stance?
Let's first look at its downsides. The front foot going across allows him to get closer to balls pitching fuller outside off. While that results in fewer edges, the possibility of him being tempted to play balls that he should be leaving alone increases radically. Also, if you're too side-on, you don't feel comfortable hitting the ball towards mid-off, because the angle of the body pushes everything squarer.
But the bigger problem is against the moving ball coming in to him. If you have a closed stance, your front foot automatically lands a bit too far across, blocking the bat's quickest path to the ball. In this case Bailey would likely be forced to go around his front pad to make contact, and that's never a good option to balls that are moving and pitching fuller.
Another big issue is against left-arm fast bowlers, because there the blind spot increases greatly. In the first ODI, Bailey nicked Barinder Sran off his first ball - possibly an outcome of the closed stance.
Sran doesn't have the swing or the pace to trouble Bailey consistently, but I wonder what happens to a batsman with such a stance against a bowler like Mitchell Starc with the new ball.
The best way to bowl to Bailey is to bring it back in on a fuller length, because he's quick to pounce on anything slightly short, and the even bounce of Australian pitches allows him to dispatch those deliveries easily.
My final verdict about Bailey's modified stance is that the pros don't outweigh the cons. So try it at your own peril. As for Bailey, he might have to reconsider it the moment he hits the next dry patch, which just might manifest as an increase in the number of lbw dismissals.