Personally, I think the Advent defences are fine.  I usually dont play Advent and when I have I have never used the Mass Disorientation ability so I cant speak to that, however, with a fully upgraded sb and full tac slots filled with beam turrets, repair stations, and hangars (2-3) I got my butt handed to me by an Unfair AI.  Basically (it was Advent as well) it came in with a full fleet of 8+ cap ships, destra crusaders, illuminators, guardians, and carriers and proceeded to wipe the floor with my defences.  It took a lot of losses but they managed to do it, and rather quickly too.  I guess what I'm getting at is that Advent defences are not impenetrable, just very powerful, something they deserve since the idea of their defences is synergy, just like with the rest of their forces.  An Advent sb or Advent turrets on their own are inherently weaker than their counterparts but when combined together (just like an Advent battleball) they become truly fearsome and tough to defeat.  I say leave the Advent defences alone, not only do the Advent need an area to be stronger than the other races but their synergistic (spelling?) effects go perfectly with the theme of the Advent.

Edit:

I meant to post this in Annatar's thread about the Advent sb but somehow screwed that up .  I'll repost there as well.