I'll put the cap on this.
You can recruit 5 fighters starting out. Over time, as you get more money, you can increase your maximum number of fighters. As that happens, you spend more time playing the game.
This is done to start people into the game slowly, and not overload them early.
With all that said, I won't be changing the time between resets. It takes people enough time to manage their large stock of fighters already. Adding in 3 more resets during a day would likely disrupt that pleasant balance that currently exists.