If you really want to see the greatest LH hitter of all time hit, you need to look at Ted Williams swing. You know what you will find? You will find that Ted had much more of a RH hitters swing only from the LH side of the plate. It was not "pretty" in the sense of pretty LH swings. His stride was short. His hands were quick and always inside the baseball and his swing was shorter than the usual LH hitter's and his bat stayed in the hitting zone longer when compared to the typical LH hitter. His real advantage was that he took a RH hitter's swing to the LH side of the plate where he would see mostly RH pitchers and he perfected that swing.
If you see Ted's swing, you will see much more of Mookie than you will see of Beni who's stride is regularly too long, who's swing is regularly too big and who sometimes does not even keep his hands inside the baseball.
Want to understand how much of a difference taking a RH hitter's swing and perfecting it from the LH side of the plate made in Ted's performance? Look at Ted's career splits. Not saying taking a RH hitter's swing to the left side of the plate is easy. In fact its darn near impossible. LH hitters struggle with keeping enough top hand in their swings, often realize it then overcompensate. So they are very often going from too little top hand to too much top hand. But the dominance of the bottom hand and the front shoulder is what leads to the LH hitter typically having a prettier swing than the RH hitter. It leads to a longer stride and the combination is generally what is defined as the "pretty" LH hitter swing.
Most really good RH hitters do not take the long stride more common to the LH hitter and neither did Ted. The short stride also allowed Ted to generate tremendous power from the lower body which is much harder to do with a long stride. See how much taller Ted stands in the box from beginning to and of his swing than somebody like Beni who sometimes look like an old style drop and drive pitcher throwing because he takes such a long stride in the batter's box.
Ted had none of the characteristics of the typical LH hitter other than his swing being just slightly bigger than the typical RH hitter.. But Ted had the advantage of using a great RH hitter's swing from the LH side of the plate. It was a tremendous advantage to Ted who was always going to see more RH pitchers than Left...true today as well assuming a hitter is not platooned. Look at video of Ted's swing and look at his splits. That is all it will take. Remember, the guy had three years hacked out of the middle of his career. It really does not effect the argument other than to imagine what his career totals would have been for hits, HR's and extra base hits had he played those three years.