I am not sure what you mean. In general, ships don't get new traits as your rank increases.
Higher level ships have more and higher level Bridge Officer slots, allowing them to use more powerful skills.
As a Captain, you also acquire new powers.
Science Captain abilities that are useful for healers.
Particularly the latter is very potent, reducing the damage your team's shield takes significantly.
If you mean Bridge Officer Skills/Powers, there are no Commander level skills that heal damage. I would suggest looking into Scramble Sensors, as this disrupts the enemy team's offense and healer, and thus makes your job a little easier. (Assuming you really want to focus on healing).
The best healing science vessel is probably the Nebula, as you can mix the best science with some of the best engineering heals.
A "classic" science vessel with the regular BO configuration, I would look into a build like this:
Tactical: Tactical Team I, Attack Pattern Delta I
Engineering: Emergency Power to Shields I, Extend Shields I
Science: Scramble Sensors, Hazard Emitters III, Transfer Shield Strength III, Hazard Emitters II, Transfer Shield Strength II, Science Team I, Science Team I
If you want to be a little more defensive, then you could take EMergency Power to Shields II instead of Extend Shields I.
That is still missing a power for the Ensign slot (I would suggest going with the Deep Space Science Vessel or the Fleet Support Vessel on the KDF side)
Tactical: You will probably have to pick an offensive choice, I might go with HIgh Yield Torpedo I.
Science: You can't really use more heals, and probably also best pick something to aid your team's offense: Tractor Beam
Engineering: Emergency Power to Shields I (and now you should definitely pick up either Extend Shields or Aux2Sif1.
Carrier is more or less identical, except BO setups and weapons (Obviously I wont be relying on torpedos with a flying whale):
Weapons 1 Array either end, rest Polaron Turrets (for their proc) - Replacable with 6beam FAW for PvE
TacTeam1 - B:TSE2 - APDelta2
EP2S1 - EP2S2 - ASIF2 (alt BO have ETeam3)
SciTeam1 - TSS2 - HE3 - FBP3
TSS1 - HE2
(Tactics, Ill launch pets and start healing.. Once a few ships are beginning to shoot me (ideally Ill catch an escort about to Alpha me) I'll Delta2 and Scan3, and use my FBP - Fully Auxed, that will hurt .. alot.
The idea is to capitalize on the huge heals, even on unconsoled Hazards, while boosting TSS (and FBP I believe)