Yes, I keep bringing up GSB as an example of how strategic (i.e. AI-controlled) combat "should be done"... provide lots of options for the player to set strategies beforehand (i.e. more so than SE5), and then let the lasers fly!
The trick with incorporating that into a 4X game is that it's not just a single fleet engagement - you might have your one fleet encounter several enemy fleets of different compositions on the same turn, and you don't even know what you're up against until the turn processes, at which point it's too late to set orders, at least in PBEM... in single player and network games, this could work, but then in those scenarios, you could even allow the player to control the ships if he so desires!
So for PBEM games, we'd have to have some REALLY complex fleet strategy options for this to work properly... conditional branching of strategies, or at least a wide variety of target prioritization and retreat condition options, taking the best from SE5 and GSB! This will definitely take some planning... input is welcome!