Romeo has been banished. Is this ruling by the Prince fair?

I knowst why the fair Prince of Verona banished my lord, but I do not see how this decree is proper. Tybalt slew Mercutio, which means that he would have paid with his head and then Romeo’s hand shed Tybalt’s blood. This would have happened anyway, and therefore the Prince should give Verona’s people another warning. Romeo dost not Tybalt wrong, because he slew Mercutio and if Romeo hadn’t killed Tybalt than surely Tybalt would have Romeo’s head as well. Mercutio was the Prince’s kinsman and therefore murdering Mercutio deserves twice the normal penalty, Romeo dost Tybalt a favor for surely his punishment could have been far worse.  Romeo and I have just become husband and wife, and the Prince dost us wrong if he banishes Romeo. My father would never let me leave with Romeo, even when he hears of our marriage. Romeo and I might be Verona’s last chance to doff the feud between Capulet and Montague, and if Romeo be banished…Verona is doomed.