Overwatch flare is only broken for team games where it applies to all ally points. In 1v1 it is fine. Soviet radio intercept provides free recon without set-up or a cost and has been accepted in multiple commanders since day 1.
Unlike radio intercept, the overwatch flare is a dead giveaway to your commander selection and the opponent knows it is in use. You can counter it with sweepers or use it for counterplay using indirect fire units.
