As dreadnaughts are the largest ship in the game and also serve as the name of this game, why not make them more powerful and balance this with less exp earned from kills and more death punishment, like more score and exp for the enemy and greater respawn time for the player?
These changes can also be done to destroyers, and for covettes we can do the oposite. For exmample we can give dreadnoughts have 1.5 time the damage and health they have now, and 2/3 for the corvettes, at the same time dreadnoughts earn 1/2 exp from kills, while corvettes earn double.
After all, it is strange to see that a tiny corvette is as inportant as a huge dreadnought, and all thoes weapon batteries on a huge dreadnought actually do less damage then several small guns on a destroyer.