jfjohnny5 The problem with stock weapon ranges is that they're so short relative to the size of the build box. This forces larger ships to get so close together than their bounding circles intersect, which means they can interfere with each others' rotation. It also means that a ship may be unable to find a range where it can exploit long range weapons if they aren't placed at the front of the ship, or that short range weapons not placed at the front of the ship may be unable to reach the enemy, possibly even if the ships are so close they have collided.
By making the build box larger you increase the range weapons must have to not cause these issues, and just doubling the build box erases all the good you've done by increasing ranges. Even a 50% increase undoes much of it.
If you build to a price your ships will be smaller in the mod if you use anything more advanced than frigate level, and all large weapons are battleship level. If you build to a volume your ships will be more expensive. It's a consequence of having large or expensive tech tree components. The tech rooms themselves cost money and they require the ship to be larger to fit them, which increases its surface, which requires that larger surface to be defended. At the only tech level that includes the large weapons that are your reason for increasing the build box you're carrying a staggeringly large and expensive complex of rooms that can only be made relatively affordable by making the rest of the ship more expensive.
If you don't intend to have larger ships in the mod, you should not change the build box, particularly since you put out a request for third party designs. If anyone wants a bigger box there's a built in build box increasing mod they can enable.