I could see that an even split in the damage between the two players would be idea.
Secondly, with the jumping on a target that causes a nudge type effect, keep in mind the player doing this would not be able to attack during that time. Similar to a regular nudge effect now where you can't kick immediately after or attack and expect to land a free hit.
This is more for leaping relatively shorter distances such as wall to mid stair case type of suicide jumping.
What this would do is give an edge to groups of players leaping off siege towers, buildings, ect into heavily populated areas and at least giving them a chance to react.