I wanted to try to specialize the three races better, if it was at all possible. I wanted to do the following.
General Changes:
Remove research lab upgrade requirements, allowing only one building to be built at one time, buit if the buildings destroyed, it can be rebuilt.
Vinci - Miana/Pirata
Heros: Giacomo, Carlini, Lenora, Venza
**Replace Leviathan with a 2 tier upgrade for Giacomo
Starting: Campaign Chapter 1 appearance
Protected Suit: Campaign Chapter 2 appearance
Divine Suit: Campaign Chapter 3 appearance, skills
**Remove statue upgrade
**Weaken Doom Cannon
**Replace Leviathan with a 2 tier upgrade for Giacomo
Starting: Campaign Chapter 1 appearance
Protected Suit: Campaign Chapter 2 appearance
Divine Suit: Campaign Chapter 3 appearance, skills
**Remove statue upgrade
**Replace Aerodrome/Imp. Aero. with Pirata/Imp. Pir. Aerodrome
**Add building Mianan Palace? (Boost power, prod. time, lower cost on vinci/non air units)
**Add building Pirata City? (Boost power, prod. time, lower cost on air units)
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Vinci - Vennucci
Heros: Doge, Pulitore
**Vennucci\Doge Infantry
**Replace Clockwork Spider with Doge Walker
**Replace Doom Cannon with Doge Hammer
**Replace Pirata Flyer with Gun Flyer
**Possible replacement of Clockwork Man
**Remove Smelter upgrade
**Replace Mine with Mining Operation
**Add building Sky Crusher (With upgrades to lvl 2 & 3)
**Add building Doge Square (Possible upgrade for Glorious Statue?)
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Vinci - Condottieri ?
Heros: Battaglion, Distruzio
**Add building: Condottieri Castle
(Boost power, prod. time, lower cost on Condottieri units)
**Replace Mine with Mining Company
**Replace Imperial Musketeers with Renegade Musketeers
**Replace Clockwork Man with Condottieri Soldier
**Replace Clockwork Spider with Condottieri Knight
**Add Condottieri Dragoon
**Replace Steam Cannon with Condottieri Cannon
**Remove Juggernaut, Leviathan
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Alin - Royal Army
Heros: Arri, Andromolek, Belessari
All other units standard
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Alin - Guardians?
Heros: Dakhla, Damanhur, Thuran
All other units standard?
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Dark Alin:
Heros: Sawu, Marwan, Kharga, Mephis, Baharya, Buto, Theben, Mendes
**Add Units:
Giant Spider > Elder Giant Spider > Bazek The Spider Queen
Glass Golem Hero
**Dark Glass units instead of regular units, appropriate building changes with exception to city
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Cuotl - Fallen
**Replace Sun Cannon with Seige Elephant
**Remove Sun Jaguar
**Remove Sun Idol
**Remove City of Vengence
**Remove Death Snake
**Remove Death Sphere
**Add Bezerkers, Barbarians
**Add Fallen units in addition to basic units
Cuotl - The Gods
Hero, Czin, Xil, Shok, Ix?
**Replace Quetzal Fighter with the Kuk Fighter Bomber
**Add Moon Gorilla
**Add Building: Eye of the Gods
...something like that.
Sure it would probably be really difficult to do, but it would still be interesting to try to do if it was possible.