A simple suggestion for the potara Fusion.
This feature would add a new npc the old kai, he would work like korin requiering good alignment.
If you have a good alignment then you can learn skills like mystic, and there would be an option to get potara like the senzu option.
Now for the actual fusion it would work the same as the fusion dance in which the attributes are doubled. The benefit of potara is once equiped and within range of someone else who is also wearing the potara you instantly fuse and it would be opposite to fusion dance instead of the weaker player getting double attributes it would double the stronger player.