Why is your leader heavier than your mainline? Should be the other way around. Are you using 10lb mainline with 20lb leader now?
Is this a legitimate question or a troll? The leader is where most of the force is when fighting fish, especially if you lose tightness and get sudden jolts. It's also the piece of line most likely to get caught on a rock and get snapped off. Heavy leader = less dropped fish.
When fishing for Giant Trevally, I use 60lb mainline and 100lb leader. When fishing for big Snapper, 20lb mainline and 40lb leader. This is pretty much the standard across most fisheries around the world. Obviously there are exceptions, like when you are trying to entice a bite on a picky fishery, so you size down your leader...but as far as fighting fish goes, having a heavier leader allows you to be much more aggressive. It should also be taken into consideration that when I talk about mainline it is strictly braid, which outperforms its test rating by quite a bit. Apart from the obvious fact that lighter leader = potentially more bites, I can't see any performance benefit from doing this.
Funnily enough this is something I have been asked 2-3 times since moving here. Not sure I quite understand the reasoning behind the thought process, maybe you can enlighten me?