Corvette rush: Early game Advent only?
The reasoning being that advent rushes are key to advent's weak early game economy. TEC players would be able to research corvettes at tech level 3-5, the vasari somewhere around that tech level as well. Why do all the races get the same corvette tech at the same time? LRF's are going to become more worthless if the design ideology of the original game isn't followed...
The other races have many other advantages, and the TEC have already proven that they can hold the line against an advent rush without needing corvettes of their own(hint, upgraded repair facilities). I can see the vasari struggling against a corvette rush, but then they will also have access to very strong armor upgrades early on, very tough capital ships and strong flak ships...so corvettes won't be nearly as effective against them.
Corvettes are very effective against advent capital ships, so now instead of advent capitals getting butchered by lrms, they are quickly butchered by corvettes. Considering they have the lowest HP and armor of the 3 races, you will still have the tried and true advent fleet failure due to loss of capital ship and planetary bombing capability.
TEC defending against advent corvette rush relies on their ability to acquire a stronger economy then the advent early on. This shouldn't be hard, one civics lab gives them all the tools they need to do this.