let me give you three simple reasons i believe Herod's didn't see much play in the past..
King David.. before the ignore ruling change King David would practically walk in on a Herod defense.. that has now changed.
Ehud/Ehud's Dagger.. pretty much anyone running Herod's is expecting this, and while it can be almost a free soul, Herod's Temple and Herod's Dungeon are easy ways to take care of this.
Speed. for the most part, there are simply faster defenses. now with Fortress of Antonia, you can get out your Herod's pretty quick through reveal if you have a decently fast offense, or a way to search out Fortress.
overall Herod's are now a very powerful defense. i don't think that you would have a lot of trouble blocking with a decent Herod's defense.