In case you missed it, Mahi-Mahi Resort will be closed for “renovations” 10/15 8PM ET - 10/17 10PM ET It will be out of rotation during this time, but looks promising for a much needed Mahi rework!
If the sketches on the image suggests the layout of the new map, it's not really a big change. Why don't they just widen parts of Splatoon 1 Mahi-Mahi (particularly the straight section near the spawn), and just port that in instead?