I hope something was done about the corvettes. Beta 2 corvettes were just stupidly overpowered. 60 corvettes, 20 light frigates, a cap ship and a Titan could counter almost anything.
... I hope you have read the Change Log? I do not believe corvettes have been touched all that much as far as base damage, fleet cap, survivability, etc.
[EDIT]: Added several constraints to corvette passives so they won't affect non-viable targets.