Losing weight should improve your power-to-weight ratio, so theoretically it should help. Of course, you will probably also be getting stronger while you lose weight, so it is kind of hard to pinpoint it to just weight loss.
One thing I have definitely seen is that I have had to go back and relearn some tricks (especially thigh holds) as my shape has changed.
I don’t think you can say someone is better b/c of their size, but I do believe it is easier for smaller women to get good. It simply doesn’t take as much strength for them. Also, short women have it easier, especially in some moves like flag where you are holding your body out from the pole.
There are amazing pole dancers in all shapes and sizes! Most of all, be yourself. Learn your style and what tricks suit your body. You have a unique body, and you move in a unique way. That holds true over a pretty big weight variation.
Good luck!
Mindy