- Low maintenance cost
- Reduced crew required (if you use a system where you have X crew empire wide to man all your ships)
- Safe reactors (does not explode upon critical hit)
- Flagship (gives a bonus to other units, 1 flagship per 100 units for full bonus; or enables admiral slot - whatever it means )
- Tactical net (each ship in a fleet that have it works better with other ships that have it, best if 100% of your ships have it; this makes sense only if the player have means (via upgrades for example) to assure all ships eventually get this ability)
- Escape pod (after destroying you get a "pod" ship that auto moves to neares friendly base, you can upgrade it to another ship or disband to get some dicsount to your cost (the premise is that the crew escaped and you can use them again, so part of your military asset survived))
- Fully AI managed (no crew, immune to some weapons, cheaper maintenance, vurnerable to viruses and electronic warfare)
Don't forget you can mix the traits, A+B, A+C, B+C, this can make a veeery interesting mechanic. Overall I think at least some of the abilities should be reused in other ships (in different configurations).