A summons must be issued and provided to the other party. They can waive formal service of the summons, but if they do not sign and return the waiver you will have to have the summons served upon him within 120 days (plus any extensions ordered by the Court).
I agree that a Summons should be issued in every case and given to the defendant. The Waiver of Service of Summons and Entry of Appearance should state that the defendant has received the Summons and lawsuit and if there is no Summons issued they can't legitimately waive it, right?