Is there any thought to giving ultra fast ships (both tactical and strategic) the ability to avoid combat?  This way a small, fast scout could shadow enemy fleets (hopefully via order).  As long as the enemy fleet remains in sensor range and the scouting ship has more moves it will remain in the shadow operation.  Crew skill and tactical speed rolls could be done each turn to decide if the scout slips into weapons range and takes fire.

Likewise, if a very fast ship were attacked by a slower fleet, it should have a chance of avoiding the combat.  

I'm thinking SR-71 tactics here.  It didn't need to fight back because nothing could stay with it.  To shoot it down you had to coordinate an attack.  The tactic is quite common in WWII navy games too.