After having played Space Marines for quite a bit in this beta branch, I feel that while the new call to arms is an improvement over the old one, the debuffs applied while active are way too heavy. From what I've seen boarding is still too effective considering that activating call to arms usually means losing the fight, as the 1 troop damage reduction is not worth all the debuffs.
So I think that call to arms should receive a couple buffs:
-Make the damage reduction scale based on the ship class(1 for LC, 2 for C/BC, 3 for GC and 4 for BS) or depending on how much crew you currently have in the ship.
-Make the debuffs less heavy: shield regeneration slowed by 50%, manouvres available but 50% as effective, ship speed still reduced by 50%, fire rate debuff 50%, keep the stances disabled.
Other than that the game is very fun.