Space Marine Chapter traits

[Panfilo]

A way to make Space Marines more effective is to have each individual Chapter get some individual strengths. Usually these just improve them in a particular aspect, so that the player can choose a Chapter based on what kind of fleet they want to take in battle. A key thing here is their Honor the Chapter ability, which appears to account for the premium you pay on many of their lighter ships. Each Chapter would get a unique version of this ability, as well as a unique Skill and unique upgrade.

Ultramarines Would be the swiss army knife Chapter, good for beginners or for players that want versatile bonuses that will benefit them no matter the fleet composition.
Honor Ultramarines - Also grants a bunch of little offensive and defensive bonuses over 60 seconds.
Maccragge Prevails! - An AoE buff that provides even more bonuses across the board over 60 seconds, activating it resets the cooldown of Honor Ultramarines. Activate both when you get in range for a nice boost in performance at just the right time.
They Shall Know No Fear - Enemy boarding actions (all types) reduce the cooldown of your own boarding actions.

Blood Angels take the Space Marines strengths to the ultimate limit, being all about assault in the face of horrific odds with zero hesitation.
Honor Blood Angels - The boarding action does increased crew damage and crit chance.
Death Company - Replaces standard boarding, gives additional boarding attempts, crit chance and longer range of the ability.
Black Rage - Any time you receive a crit you immediately launch a 'free' lightning strike at random to a valid target in range, with a cooldown before the passive can be triggered again. Combined with other abilities, this can let you really pile on the boarding attacks onto nearby targets in quick sucession.

Dark Angels integrate some Psyker abilities in order to root out their fallen bretheren.
Honor Dark Angels - Lowers enemy Leadership when the ability is activated.
Deathwing Terminators - Replaces Lightning Strike, allows Lightning Strike to activate once the enemy ship's shields are under 10%. If the target got reduced to a Drifting Hulk, will attempt a minor boarding action against any enemy ships that get too close within 60 seconds.
Battle of Wills - Enemy ships close to the flagship have reduced leadership, accuracy, and crit chance.

Iron Hands emphasize cybernetics and technological augmentation into their tactics which gives much needed survivability.
Honor Iron Hands - Heals some HP on the ship over 30 seconds, scales with ship class.
Overcharged Implants - Replaces 'Brace for Impact' command. Turret accuracy is further improved, and 10 seconds after any boarding action is performed the ship is immune to crits and abilities that reduce its armor rating.
Cybernetic Failsafe - If the ship becomes a Drifting Hulk it will add a few crew points after 10 seconds and become active again on its own.

Space Wolves are among the many Space Marine chapters that emphasize close-in fighting, using the variation in their geneseed to work to their advantage. Their skills make working in a pack more effective with flat buffs that disproportionately benefit cheaper ships.
Honor Space Wolves - The 'Honor the Chapter'ability gets two charges before the cooldown triggers, making it more cost effective when taking lots of smaller ships.
Howl of Victory- Flagship ability that buffs all allied ships by a flat amount, making it really strong on escorts.
Pack Hunters- Replaces standard boarding ability. When boarding from one side, automatically triggers an identical boarding action on a random enemy ship on the opposite side. Jam in between two heavy ships to board both simultaneously!

Salamanders specialize in heat weapons which tend to work really well in breaching hulls and clearing out enemy crews.
Honor Salamanders - The ability has a 100% chance to start a fire on the target ship.
Purge with Flame- An enemy ship instantly takes hull and crew damage based on the number of fires/duration present, and removes all fires on the enemy ship aftewards.
Melta Warheads- Standard torpedoes, bombers, and bombardment cannon have an increased chance to cause fires.

White Scars are like Space Mongols that value speed and cavalry-style maneuvers. They are well suited to helping your fleet close in on their targets, and work well for faster enemies that try to kite you.
Honor White Scars - The ship has increased boost regen, speed and maneuverability for 30 seconds.
Surge Forward- All ships in the radius temporarily gain improved speed and maneuverability while boosting, and do not get revealed while maneuvers are active.
Wild Hearts- Strike Craft and boarding torpedoes have boosted speed. This is boosted further if Surge Forward is activated.

[A Make-A-Wish Kid]

Raven guard and Imperial fist ideas?

Raven guard would be a LOS/Stealth buff, or something like after a boarding action the enemy LOS gets crippled like the Augur disruptor bomb.

Imperial fists would be a defensive buff, either to critical hits, or the ability like belt armour from BFGA1 to ignore the first critical to a system.

[Hannibal0216 도마도 재배자]

Orrrrr........... we could just go back to BGA1 customization so that we could customize the ships to match the chapter's characteristics

[Panfilo]

I'd rather each chapter get something a little unique to set it apart from others. Being able to board from both sides, or prevent an enemy from recovering a hulk, or triggering mutinies faster would be more interesting.

[Takoita]

Imperial Fists could improve perfomance of basic macrocannons, in a similar way they did with their 'bolter drill' on tabletop.

[Panfilo]

Oh, that's another good one, Takoita. You could go Macro-heavy with them as an example, to pump up their mid range firepower. Not something that would normally be worth it with that faction, but if Imperial Fists improved them A LOT then it would be a cool strategy to use against some opponents.

[Reginleif]

Space marines need to get buffed, period.

[Syzy]

No, Space marines need a Unilaterial rework, not just subfaction abilities.

[Panfilo]

Subfaction abilities are a stopgap, but I agree they need to be fundamentally reworked.

At the same time, it would be nice to have the chapters better defined from one another. This is something that really bugged me in the first game that they missed the ball on :

In the first game, Imperial Navy had the 'Astartes' favor, which was generic. OK, fine. But when they released Astartes as their own faction, instead of having 4 different chapters function as favors they went a different direction, with one really good favor (chapter master) and the rest pretty mediocre. This made their fleets really samey, because there wasn't a whole lot of variation in fleets.