2. That armor requirements grow exponentially (surface of a sphere is power 2) which means that with a sufficiently large x it will exceed linear growth.
Two things:
First, a mathematics nit to pick: Armor requirements grow exponentially
as a function of size " (added implied function dependency) is a mathematically incorrect statement. Growing exponentially means that the variable that is changing is in the exponent, e.g. e^x. Total armor mass to get the same depth of armor grows like radius^2 = volume^2/3 = mass^2/3 (since volume is proportional to mass in Aurora). This is polynomial growth, which means the exponent is a constant as a function of the variable. Linear growth is mass^1. Since 1 is bigger than 2/3, this means that the percentage of the ship's mass required to get the same depth of armor goes like mass^(-1/3), which
decreases as mass grows (a ship that is 8 times as big in volume/mass (radius twice as big) only needs 4 times as much mass to get the same depth of armor (1/2 as much as linear growth), so it can devote more internal mass to mission systems. Or it can apply the same bonus mass to extra armor, resulting in 8 times as much armor (same percentage) but more rows deep.
Second, the reason I'm making a big deal of this (besides lobbying for correct usage of the concept of exponential growth) is that this (bigger ships are more capable than an equal mass of smaller ships) has been a primary design goal by Steve since Day 1 of Aurora. The reason goes back to swarm fleets in StarFire. In StarFire, a common tactic was to design hordes of small ships (corvettes) that would overwhelm an equal mass/cost of large ships. Steve wanted to design the game mechanics to counteract this tendency, so he consciously set things up so that large ship's armor scaled slower than linearly, while pretty much every thing else scaled linearly. The only thing that I can recollect where small ships had an advantage has already been mentioned upthread; that very small ships didn't require a bridge so you got a mass savings there. For everything else, I'm pretty sure that if you glue two identical ships together (including armor mass), you end up with one ship that goes at the same speed and has twice as much as everything. You can then get savings around the margins - only need one bridge, plus with the new engine rules you can replace e.g. 2x25 engines with 1x50.
So the "complete" picture is that the game mechanics are explicitly set up 1) to mostly be linear and 2) to make large ships (in the limit of large ships) more efficient than small ships - this can be seen in Charlie's numbers. The major effect of the size-50 limit is that this efficiency growth is less pronounced (because you can no longer make bigger, more efficient engines), which takes you back to the old days where engine efficiency didn't depend on size. (Note that I wrote a ton of doctrine posts in those days talking about how this effect of everything being linear heavily favored single-role ships for things like survey and jump engines.)
John