Sure, but that's a different game. If you want tactics, play a tactics game. I doubt you'll find many set in space, anyway, where there's no such thing as high ground or terrain or choke points.
And in GalCiv it's not quite so simple as "I have lasers, you have point defense, I win." That point defense still counts for some defense (specifically the square root of its nominal value), the ship's hit points could still soak up enough damage to let it win the battle, the enemy could have better logistics and therefore more ships in his formation, and even if you wipe them out, they get to fire at least once, so multiple battles will wear your ships down anyway. Your enemies will also start countering your technology, too, and you're likely to start seeing ships with two or three different kinds of weaponry and defense by midgame. Beyond that, if you get to a point in the game at which your fleet is completely unstoppable, there's little point in continuing. You can simply force everyone to ally with you and win the game right away.