Are you custom designing units? Are you building them from fortresses? Load up pariden units with magical equipment, then use scrying pools combined with city enchantments to give them fire attack, initiative, health bonuses.
You'll be able to mage staff-wielding units that can kill juggernauts before they'd ever get up close.
Juggernauts are amazing but they can be killed somewhat easily. Pariden requires more detail management than yithril, but they are an awesome faction.