Because crits suck and aren't fun right now. Also included are some suggestions to change crew, after discussion with Ashardalon and Brohan. Reworking them to better fit in with slow paced gameplay, as opposed to it being possible to suffer instant, debilitating critical hits that you cannot fix, would be good.

Numbers are for example only, actual balancing would be done by people who do the balancing.

When a ship receives a critical hit, a system will be chosen to receive the critical hit. A minor critical is chosen from that systems critical hit table and applied to the ship. Systems that receive a critical hit are degraded and lose performance, with the minor critical applying a small statistical penalty to the system affected. A shield crit may reduce it's capacity by 5%, and an engine crit may reduce it's top speed by 5%. A system may only receive a certain number of critical hits before it is counted as destroyed, and cannot be repaired.

The amount of critical hits a system may receive before destruction is determined by the ships class, the systems of larger ships must receive more critical hits before being destroyed. Additionally, the penalty of a minor critical is reduced as ships become larger. This is intended to replace the critical reduction larger ships receive.

Example 1 -
A Retribution Class Battleship receives a critical hit. The critical hit is applied to the power generator. This critical hit then rolls against the critical hit table for the power generator.
Example Critical Table
40% - 5% reduced shield capacity
40% - 5% reduced shield regeneration
15% - 10% reduced shield capacity

NON-SYSTEM CRITICAL HITS
To combat the extreme effectiveness of high amounts of one thing, through-armor critical hits and fires will be subject to a scaling function to reduce their strength. Through armor criticals will penetrate less armor as the damage of the projectile increases, and fires will do reduced damage for every fire after the first, increasing for each additional fire. If a fire were to end, the remaining fires will increase in damage, while still doing less damage than if the additional fire was still there.

STANCES
Minor critical hits may be repaired through activation of the Repair stance. While active, the ship will repair a minor critical hit after a certain amount of time, continuing until the stance is deactivated. During this time, the ship will also be penalized.

A new command group will be created to hold the new Repair stance, as well as the Call to Arms stance. These will not share cooldowns with ship stances (Lock-On, Brace For Impact, Reload), additionally, they will not share cooldowns with each other allowing rapid switching of stances if required. Although once deactivated, the stance will have a short cooldown before it can be re-activated.

BOARDING
Boarding Actions will focus on causing critical damage to enemy ships. Upon succeeding a critical hit roll, a system on the enemy ship will be afflicted with a minor critical hit. No additional crew damage will be inflicted.

CREW
To facilitate critical focused boarding and make hulking very difficult, the crew levels will be split into 10 or more levels. When crew is reduced to the next step, the ship will suffer penalties to various statistics. These penalties become more severe as the crew steps are reduced further. In addition to penalties, certain steps may apply critical hits. These levels would be separated into 3 different tiers, with each tier having more crew than the next.

As an exception to the rule, Tyranids will have very low, if any crit chance. In exchange, their crew damage will be increased highly, giving their faction a niche of killing crew and hulking, without causing any critical damage to the ships. In Contrast to Space Marines, who's surgical strikes and low troop numbers will excel at taking out systems, but not kill much crew.

Example 2 - Crew Steps
A Battle Barge has 11 crew steps. The first 5 crew steps will have 10 crew, while the next 5 will have 20. The final step will have 50.
Step 1-5 - Each step reduced reduces firerate by 2%
Step 6-10 - Each step reduces firerate by 3%
Step 11 - Ship becomes hulked and suffers critical damage.