Several reasons.
My right leg is much stronger, almost every other movement I perform indicates that I should plant RL (as you can see in the lr vs rl thread I created).
Without the ball I jump exactly the same LR or RL while never practicing RL and being quite abit less efficient because of it. Since my right leg is stronger I can use a faster approach without collapsing.
And the final reason, I think RL dunks for a right hander look much smoother/better in general.
Its been on my mind for almost 2 years now, and since I wont be jumping for another 2 months I thought should make the switch this year and see what happens. Worst case scenario is that Ill be jumping exactly the same but with a plant I like better.
If I remember correctly you said that your rl is quite abit worse. If thats the case making the switch most likely wouldnt be worth the effort.