MP levels from campaign

Just started playing co-op with a friend over the weekend. I Played only multiplayer for the first week. I was noticing there are a good amount of areas they could use from the campaign for MP arena maps. Reunion and Sword of Sangelios so far seem to be the best. I would love for the Kraken interior to be an Arena map. I would much prefer reused campaign assets to the look of forge style maps.