It is more than what player could get in pre-0.7a releases when fleet size was dictated by Fleet Points (0.5 era) or Logistics (0.6 era). Back then, assuming maximum points (max Leadership and Fleet Logistics), player could bring about 30 thirty frigates or 3 to 4 capitals or something in between with medium ships. If player was unskilled in Leadership, he could only use five frigates or a single Conquest (battleships or Astral were impossible to use without taking penalties if unskilled in Leadership).
Of course, that also applied to the enemy, and their fleet size was no bigger than the modern 200k named bounty. Now, enemies have gigantic fleets (either sixty to hundred ships during the first 0.9 release, or ten to twelve capitals and the rest cruisers for today). Meanwhile, PPT has remained mostly unchanged since 0.6. So while fleets have bloated over the releases, PPT has not kept up. Also, max map size has shrunk from 500 to 400.
That being said, increasing the fleet cap is pretty reasonable, and I did it on the last release. I find it less useful on this release because carrying around a bunch of ships eats into your skill bonuses anyway.
More Phantoms to crank raiding power!
I find map size the biggest constraint to fleet battles. The max of 500 needs to be restored (or better yet, raised to 600+ with bloated fleets in modern releases). 400 is barely big enough. 300 is unacceptable, turns fights into Star Control style duels, which drags fights out longer (thanks cowardly AI). I like fleet battles, not tag-team fighting game matches.