It appears that Warhawk's beta will grow in a similar way to the Home beta, in that waves of people will be accepted to try it out.
PlayStation Underground has just sent out emails to people who signed up for the beta but failed to be accepted the first time telling them to stay tuned. So we expect more beta spaces to be available shortly.
Also, while many beta testers have been experiencing constant freezing issues, Incognito plans to fix the problems as soon as possible. Hopefully the second wave of beta testers won't have to experience such grievous issues.
Be sure to check your inbox in the coming weeks for more spots in the Warhawk beta.