A few changes should be made to space combat so that different ships can fit their assigned roles better. Here is a quick list:
Reduce the shared cooldowns on officer powers that use the same system.
Give cruisers an increased rate of moving their shields.
Reduce the cooldown on powers that exclusively support team members.
Reduce weapon power consumption on ships with many weapons.
Increase the turn rate on cruisers to slow but not frustrating levels.
Make stealth detection work at useful levels.
Reducing the shared cooldown on powers that use the same system is nescesary for some roles to truely function. A ship cannot be an effective supporter if it can only use a related power once every ten seconds. If someone enjoys using Tachyon beams enough to equip two why do they need to be punished with a 10 second cooldown between firing them? This cooldown should be around 3 seconds long to prevent people from unloading all their powers in a single pass, but 10 is too much.
If cruisers could move their shields from one side to the next quicker than other ships their big broadside and lack of maneuverability would be counteracted by their ability to bring their shield strength to the exposed side more quickly. Currently bigger and slower ships are easier to kill than smaller fast ships, simply due to the fact that you have to take out only one shield on them, while fast ships can turn quickly enough to present all four shields.
Powers that heal or strengthen team members but not the own ship should be stronger than powers that only or also affect yourself. This would be best accomplished by giving them drastically reduced cooldowns, so that several players working as a team acctually have an advantage from using support powers on each other rather then everyone just using their own.
Currently there is not much reason to fit more than 4 phaser banks on any ship, even if the ship could theoretically fit 8. The reson for this is that power consumption on shots becomes so drastic that sustained attacks are not possible. Bigger ships with more weapon slots should draw less power from the weapons when they fire. It is only reasonable to assume that a ship with more weapons has more "ammo".
Some cruisers turn too slowly. Yes, they are supposed to be big lumbering ships, but something as trivial as scanning an anomaly or collecting some loot should not take frustratingly long, no matter how massive the ship.
Stealth detection in its current form only works on ships that are within about 2km of the science vessel. This is a problem because a Klingon who is trying to avoid combat will turn and run long before he gets within 10km, a klingon who wants to engage in battle will decloak and fire between 7-10km, so at no point in time can the cloak detection acctually discover someone who is trying to run or about to attack. Chance to decloak should start at about 15km and comare the aux levels of the cloaked and the scanner to determine if they are discovered so that a science ship running at 35 aux cannot decloak a klingon ship running at high aux effectively. Decloaking is a support role, only science ships who play as a support ship should be good at it.