Might as well take a shot at designing a map I'd like to see in Splatoon:
St. Levia's Courtyard
Overview
St. Levia's Courtyard is the courtyard of a private school. It is named after the mythological Leviathan, a sea creature of unimaginable power. Yet despite the lofty name it stands at a measly 1400p or so--less than even Blackbelly Skatepark. Thus, fights tend to be fast-paced and close-quarters.
However, the map is different from Blackbelly in that there is no central pillar; instead, the largest of three water fountains is there. It of course serves as a water hazard for those who jump around willy-nilly. Close by on each side is a small foam barrier, one of the other fountains, and a tower that can only be climbed on the side behind the un-inkable wall. However, the towers are not so high that any Inklings who climb them are immune to enemy fire.
The tallest points of the map are the balconies on either side of the map, diagonally across from the big fountain. Foam barriers on the side facing the center prevent Chargers and Splatlings from locking down the area nearby, forcing them instead to target straight ahead or towards the side behind the fountain.
There are also several grates that function as rest points for climbing walls as in Flounder Heights. In particular, there is an L-shaped grate to the right of the spawn point which barely conceals a secret passage towards the elevated side areas. Those areas themselves have a single foam barrier, each closest to the edges of the map, but are otherwise relatively open and great for grabbing turf. Meanwhile, to the left of the spawn is a series of ramps that lead to the bottom floor and an offshoot grate that overlooks either small fountain. Finally, the center path from the spawn point is a deep drop to an enclosed area similar to that found in Arowana Mall.
Ranked Mode Changes (included in a Zip file with this post)
Splat Zones: The splat zones are located on the bottom floor, opposite the central fountain. They include the ramps to the side areas. To facilitate traveling around and gaining ink for specials, the other fountains have been removed. Additionally, ramps have been added near the grates behind the balconies.
Tower Control: The tower is located dead center over the fountain. Ramps have been erected on either side so that the players can climb aboard. Once an Inkling has taken control of the tower, it will travel in a winding path up to the goal on the left of the enemy's spawn point.
So that enemies have a chance to take back the tower, some alterations have been made to the map. The mini-towers at either end have been moved to make room for the tower's path, and the small foam barriers have been removed. On the balconies, the foam barriers have also been removed so that Chargers can attempt to keep the tower safe. There is also a new platform next to the winding ramps leading to the bottom floor and a new grate bridging the two paths near the spawn points.
Rainmaker: This mode has the most alterations over the basic Turf Wars layout. First, like the tower the Rainmaker is located dead center over the big fountain. However, in addition to the ramps there is also a platform and some grates over the fountain to make room for players to fight to break the shield. The goals are located to the right of the enemy spawn points, just before the grates over the secret passages.
The base below the spawn is now surrounded by non-inkable walls, and the left path is blocked off by foam barriers to make RM carriers use the grate bridge which is also present in Tower Control. Additional small barriers are present on the bottom floor and near the goals. The ones on the balcony have been moved so that Chargers can no longer shoot directly in front. Ramps have been added on the bottom floor and on the side areas to help players reach the top near the goals. Most significantly, barriers have been placed to block off the side-most areas to prevent carriers from camping there.
Squid Sisters Conversations
C: All right, Marie! Teach me a hot strategy tip for this map!
M: Yeah! Um...stay in--no, wait, I already used that one. Never mind.
C: (Surprise) Wow, this school is so prestigious!
M: (Sad) If only Gramps could afford to send us there...
C: So, if I take the hyperbolic coefficient of the Mahrmann hypothenuse and add it to the Granzfeld factor--
M: Callie, stop making up words to sound smart.
C: (Happy) Look! They even have fountains in the courtyard!
M: Just try not to fall in. They're surprisingly deep.
C: (Sad) Home Ec was not my strong suit in school...
M: No kidding. I heard you burned the kitchen by accident. Twice.
C: (Intent) Fighting turf wars is fun and all, but don't forget to do your homework!
M: (Happy) Otherwise, you'll end up like her!
C: So, what was your favorite subject in school?
M: Music, of course! But also Home Ec.