Teg Had a very similar layout in my older ships for the cannons, after going up against your exodia, borrowed a few ideas, like adding extra crew...and fire extinguishers (i'm an evil captain, rather let them burn, lol) does make a difference. Though I tend to like a bit of additional armour infront of the reactors to extend life.
Agree that the electro isn't the greatest, i think it's the length more than anything (same issue i have with the heavy cannons), trying to have enough to make a difference means to shield them you're removing corridors which stop good energy flow....ultimately making them useless in the first place.
As for the centre, sure it's a chain reaction nightmare...but it does help to save on width, allowing for slightly more forward firing offense. I find usually the shields are enough to keep it alive. Might try a few more modifications with no electro's taking up space.