As IPAndrews said, all the ships are underpowered compared to their show counterparts. It think it should be balanced a little differently in the next patch, though.
For example: I pitted one Vorlon Cruiser against a Minbari Tenashi and had them fight.
Now, show-wise the Cruiser is about as strong as a Shadow Battlecrab, which in turn is much stronger than even a Minbari Sharlin.
However, in the test battles I ran the Tenashi squashed the Vorlon Cruiser ten of ten times, sometimes with as much as 90% of it's hull intact.
Also, the Minbari Sharlin win pretty easily against even the biggest Battlecrab. And that's when the Battlecrab is lucky enough not to have it's slicer turret destroyed.
My suggestion would be to increase the damage of the slicer beam some, make the slicer turret's hitpoints equal the ship hull, decrease the Minbari weapons' damage( especially considering *many* of them fire at once and that they're beam weapons and rarely miss), increase the damage of the Vorlon main turrets a fair bit, decrease the Hull strength on the Tinashi and Sharlin

(even as much as 50%, they can take way too much damage right now), and vastly increase the Hull strength on the Vorlon cruiser & transport.
Now, the ships would still be underpowered compared to the show, where a Battlecrab takes out a Sharlin with a single beam, but it would hopefully adjust the balance correctly as to 'which ship win against which', while still mantaining a gameplay balance. But that's more the job of the mission creators.
Anyone feel free to chime in on any of this.
Love the work you've done with the game guys, thanks

!