I think you should help me out. I've got a good start but I'm never gonna finish on my own. Frankly I love altered melee and feel like a lot of the other map styles often lack polish.
My map ruleset start after RoC came out and I saw how much of beta had been cut but could still be added. I'm pretty sure Naga was the cut 6th race (the 5th race was Demon) that Blizzard never even revealed back then. I also wanted to have a lot of stuff from Warcraft II. It will be interesting to see the Naga play against the other races in open sea.
What I have done:
5th Hero for Basic Races: Archdruid for NE, Shadow Priest for Undead, Elven Ranger for Human and Assasin for Orc. The first 3 are based on cut heros, the Shadow Priest being based on the old concept of the hero version of the Necromancer. The Assasin is an homage to Garona and seemed cooler than the calvary hero that was cut (which I may give to Chaos Orc/Demon someday).
Navies: Warcraft II style naval combat meets War3 detail. I don't have an Oil resource since it was being buggy and would make AI impossible I think. However there are oil patches at sea and you can build rigs on them and destroy them and so on. The harvest is gold, but the best ships require control of a rig to build. The Night Elves and Undead have navies with their own specialties. Night Elves have no subs but can use Hippocampi to detect them and act fast harassers. Naga of course, do not need a navy per se.
New Techs: I like tech and with all the leftover Blizzard icons from beta I've had a bit of fun with about a half dozen new techs for each race. There are foundries-type buildings that provide upgrades for the ships.
Naga: I've fleshed them out almost to the point of the existing races, but the heros need some work and it's all a little rough still. Overview is as follows:
Excellent in the water of course, no need for naval transports and can build freely on land or shallow water. Can research a healing boost for submerged units.
Heavy focus on arcane magic leaves almost no magical healing. Items and aquatic healing can offset this.
On the other hand most other magic is strong. Generally good at tricks and offensive magic. Fairly good variety of debuffs.
They don't have any mechanical units or any tower alternatives to the Tidal Guardian. Wood and string break down in water and projectiles travel with reduced force so they've mostly stopped using these. With monsters and magic they hardly miss such technology though.
Heros:
Sea Witch
High Warlord (Najentus-type)
War Queen (melee agility female with some magic)
Deep Stalker (male melee mutant with powerful offense)
Mur'gul Dream Eater (devious mur'gul caster)
New Buildings:
Supply Yard (lumber building, combat upgrades moved here)
Cathedral of Tides/Nexus of Tides (higher tier main hall)
Mur'gul Quarters (trains Mur'gul Cultists, has Mur'gul upgrades)
Artificer's Hut (Item building, Orb of Water and many common replenishment items)
Hatchery (enables Sea Drakes and Dragon Turtles)
New Units:
Incursor (took Ensare from Myrmidion, fast scout Naga unit)
Medusa (offense magic, can blind and petrify)
Mur'gul Cultist (non-slave Mur'gul caster, can Rot enemy mechanical units and buildings and summon sea elementals)
Sea Drake (very much like a flying dragon turtle)
Royal Guard (slightly nerfed, can mutate from Myrmidions after research at Nexus)
Send me a message and I'll show you the current copy. Be warned, I still need to fix a bunch of tooltips.