In my actual game, pretty much all the galaxy went for the missile weapon branch (the sole exceptions are the Iconians, but they are crappy anyway). However, I was the only player in the galaxy to actually research heavily missile defences. While I have "Droid Sentries II" most of them don't even have POINT DEFENCE!

The frigates I built have a rating of 25 missile attack/20 missile defence, and to tell you, it shows a lot during battle. More often than usually, Arcean and Altarian ships shoot for "0" damage. And I didn't told you about my "Ravager", a Large ship with 40 missile attack, 35 defence. They are almost invulnerable.

So, while my fleet have an average attack of 100 and 80 defences, I face fleets who have 120 weapon and 5 defences. It's not allright. Since "first strike" option has been removed, defensive technologies must be prioritized a lot more by the AI.