The Coalition can hold it's own just fine thank you.
It isn't about ship numbers, but the quality of the units in question.
Just ask the 300:)
Everyone you ask is going to have different numbers, even in the Dev team, based off of their own opinions. Nothing is set in stone, nothing is canon.
We might turn around tomorrow and discover the Corsairs have a brand new, resource rich system they've been hiding that gives them the final edge in the OC/Corsair war.
Gallia could be a paper tiger, like China is militarily. The Worlds biggest army, but most of that army are actually construction workers or civil servants as both must be in the army.
For example the Coaliton, everyone has been called to service. Children are running the reserve fleets right now. The population swells each shipment of refugees we take in...
To guess we are or are not better than another group is entirely subjective.
The Coalition may only field a pair of battleships, and 6 cruisers. But what about it's seeming near limitless supply of gunboats/snubs? We have, in lore, three factories spitting them out, one of the size of a moon.
The point is, it's a game, and all our guesses are going to be off.