I'll tell you about my wet dream of a future skin for the Lawbringer, maybe "legendary" although we don't really know what these special skins have besides being pretty.
Basically, I'd love for the armor to be primarily inspired by Lawbringer's base model (not the more common cape version), since it's more bulky and better highlights the "tank" stereotype I like about him: big, solid, and massive. But with the obvious detail that this time he would have a cape, something many have dreamed of for characters like the Warden. I'd like an imposing cape like Juren's, perhaps a "poncho" style that completely covers one shoulder and is visible even from the front.
As for the arms, there's not much to say. For God's sake, give him Holden Cross's damn shoulder pads! It's been 10 years and they still haven't released those or Tozen's helmet for Orochi. Just give poor Law his damn shoulder pads already; they would look incredible on this skin. I'd gladly pay 42k steel for those shoulder pads.
And lastly, the helmet. There's not much to choose from since Law already has some great helmets, but he's missing one thing: some kind of ornament, like horns or a crown. A pair of horns like the Warmonger's (from Dikayosine's armor) would look incredible on him. Besides that, any kind of helmet would look really good, just please respect Law's essence and don't show his face or eyes... please don't ruin it like you did with Ramiel.
And that's really all. I don't know, you could add some more details like jewelry or whatever to justify it being a legendary skin, but with all that, I'd really be satisfied.