I think tactical is usually a cop-out against the AI.
I have found that using Strategic mode I have to pay attention to two main areas: the battle formation and style of attack (optimal range etc.) actually matters, and it helps balance out a human's superiority in design.
I have found that different formations and firing strategies are required against different races. Tactical will always be too easy when it's in a game with the complexity of Space Empires IV. I could always quash MOO2 at will (the name of the game was: plasma cannons) and it was much less complex that SEIV....
Anyhow, just my additional thoughts
Jason2