I would love to see a BSG mod. I love BSG.
How a BSG mod should be is simple to me. Battles in the mod should look like battles in the show.

Not like sins with BSG models.
Sins would be great for BSG, however quite a few things would have to be reworked:
-Balancing of the game.
BSG is less about RPS, more about tactics. Sins is already good in this in that there isn't much rock paper scissors excluding lrms, carriers, and flak.
-Z Axis. BSG uses it, sins doesn't. Fleets need to automatically use the z axis when attacking, and ai opponants need to too. Ships, cap or fighters, both should be attacking each other from above and below and there should be "top, bottom, left, right, forward, back" damage on the ships, not just "left, right, forward, back" as they are currently in sins.
-Fleet AI. Need to get rid of that focus firing on fighters and make them work in small groups of 2 or 3.
-Strafing of everything. Fights should fly backwards, turn around 180 degrees, strafe around. Cap ships should as well!
More importantly, there is a big thing of why other mods have failed at BSG:
-All they did is replace the meshes and weapons. When you do this, you have a boring as shit mod because BSG only had a few cap ships and a few fighters.
Homeworld is a good game. Homeworld with 2 battlecruisers and 1 fighter type on one side, and 1 battlecruiser and 1 fighter type on another side with just missiles and bullets is not a good game.
Alot of people will say there isn't enough variaty in BSG's ships, but there is. What people are missing is they don't need to focus on content of ships, but content on the types of tactics people can use. The abilities and leveling that sins have is pretty perfect for this.
Raptor with a strike team boarding a base star and setting up a nuke there.
Nuke missiles that fighter screens shoot down.
Scrambling fighters at the last minute so that they'll have more fuel to fight.
Managing your energy for FTL drives.
ECM'ing to knock out the AI aiming of the battlestars guns.
Those are the things BSG mods have missed which make it a good show, and without them you don't have a good game.
Just have the story either based on after they find earth, and have made a bigger fleet, or before the start of razor when there where more battlestars. But just having 3 battlestars to choose from, and 3 fighters on one side, the base stars, old raiders, new raiders on another side is really enough(though more wouldn't hurt if they fit).. There just needs to be a lot of depth to those 6 ships in how they perform and what you can do with them.
Vipers are nothing like sins fighters.. Vipers can shoot down missiles, they engage in dog fights, they have cannons for attacking caps. They're much more multi purpose, but also less replacable. They don't poop out from antimatter.