So here is the question, would a ship be broken if it could take two droids.
I would say, maybe. Probably yes. Two of the droids help with target locks, but the rest seem to help with survivability. Certain combinations might make a ship difficult or near impossible to take down. If a pilot had determination, an R5 Astromech and R5-D8, he could potentially be deiscarding all of his damage back to full hull. Additionally, an R2 Astromech and R2-D2 would rejuvinate the shields, easily. What would be worse? A pilot with determination, R5-D8 and R2-D2. Flip over all Pilot crits, discard regular damage, restore shields.
The other sde of the argument would be that the large ship would not be able to completely restore hull/shields if the opponent kept up the attack.
Three or more droids on a large ship would be a nightmare to kill. One droid, not so bad.