I have modded the Hiigarian AI to change their fleet configuration when attacking using a more human like style.(ADV 0.6)
With just 261 units Built the Hiigarians have managed to eliminate 757 units most of them Taiidan loosing only 160, sure is combat efficiency, or poor balance? I'm sure it is efficiency because My Taiidan units are very powerful, just need a good commander.
CPU1:Taiidan
CPU2:Vaygr
CPU3:Hiigarians
CPU4:Kadeshians
Most of these problems have been solved in version 0.7