Ultimately I think Heretic got the better end of the stick with this release.
>1 new weapon
>3* new enemies (Chaos Serpent isn't new but is a common enemy now)
>new episode made by Kaiser (god tier level designer)
>much better balance changes (Crossbow stronger but less ammo, Hellstaff projectiles have homing, Gauntlets of the Necromancer have higher hitstun chance, Staff has longer range, I think the Elven Wand is a bit stronger)

Hexen's new hub is also fantastic but I know it would've been better if Kaiser made it. But other than that Hexen only got a few new assets for key/puzzle items (Death Mask/Fetid Mask in Deathkings instead of the base game's Flame Mask repeat). And all the weapon updates are overpowered and make older, more interesting strategies obsolete (Cleric flechette has no purpose now, frost shards' melee is useless so no frost shards+flechette combos).