I was playing a bame in paralel with freelancer for a while just to not get to fored of one at a time.The name of the game is X ( BTF,X2,X3 - some of them as i remember now ) and personaly the game is much more balanced than freelancer will ever be.It is single player only but that is quite a good thing...there you need probably a very good frigate (cruiser) to destroy frigate cruiser and simply you cannot even dream taking on a ship that outclasses you.There are small exeptions : a interceptor (a heavy fighter) can posibly destroy a trader but that takes time and calm because one hit and your shield is gome and in x3 if the damage is 10000 and your shield is 5000 your hull will take the rest of 5000 - so this is an ideea : make shields more balanced and not allow 1% of the shield of a light fighter to block and entire heavy mortar.
Another important thing is that every ship in the game mounts a numer of shield modules (eg: a transport - the dolphin- ship can mount 3 x 50k shield module) but that depends on what ship your flying and to witch race it belongs to .... it may carry more shields or less.
The speed is individual...you cannot posibly find 2 ships with the same speed and turn rate...
Battleships,carriers and destroyers(dreads) have a turn rate so slow that flying a barge will like playing with lego.Battleships cannot be taken down by 2 bombers....you need an armada of them to take down a single destroyer.
Sorry i derivated so far from the whole threat but my main idea is that some things needs to be balanced and some does not:
-different speeds for every ship ingame (eg : more amor=less speed)
-somehow buff battleships so that 1 cannot be soloed by a cruiser
-somehow buff traders (less advanced weapons and bigger size should mean more protection)
-different shield capacity from ship to ship (probably the posibility that some ships could mount more shield modules)
I know this is a lot of work and thinking....but this would be my general idea...so its just an ideea