I use Maces ship and the reason why his ship seems faster is due to the ability
Fortune Favors the Bold: Deal physical damage to target enemy and all enemies affected by Target Lock, then grant all allies Valor for 2 turns. This ability's cooldown is reduced by 1 for each enemy struck.
(Valor: Grant the Endurance 20% Turn Meter, and reduce its ultimate ability's cooldown by 1 at the end of turn)
So essentially if you hit 1 ship with Fortune Favors the Bold it reduces the next one by 1 turn and gives the Endurance 20% TM. But if I have target lock on 3 ships and then use Fortune Favors the Bold on a 4th ship all 4 ships get hit and my next Fortune Favors the Bold's cooldown is reduced by 4. So because of the massive cooldown reductions and Endurance TM gain it can seem like Mace's ship is taking turns over and over and certainly at a faster rate than other capital ships.
More importantly though the faster and more turns Mace's ship takes the quicker you can use Convergence the Endurance ultimate ability which makes all your ships immune to damage for 1 turn and give them Offense Up for 1 turn.
How can you stop this from happening?
1. Target ships that get target locks easily first (eg. Vader's Tie, Imperial Tie Fighter, Fives' ship, etc.)
2. Remove debuffs on target locked ships with Ackbar's ship
3. Use Maul's ship to stealth all but 1 ship you can't target lock multiple ships if you can't target them
4. Keep a taunt on 1 ship at all times then that ship is the only one that can be target locked
