Unfortunately, Phit's doesn't scale damage not involving the PC... so a fight between some rogue Conjurer's Clannfear and a patroling Imperial Legion trooper will result in the summoned Clannfear being cut in half like a piece of paper whilst only being able to deal maybe 1/12 of the troopers health in damage per strike (and missing a lot). Its not only blows the PC is directly involved in that need to be fixed. ALL combat between any and all actors should be scaled properly. I've played Vanilla, OOO, FCOM, and TIE builds of this game each with DR and MOBS... and still none of them really ever got the combat to the realistic deadliness I'm looking for. Always one side of the fight seems overpowered, or both sides are just ridiculous pools of health... If creatures can't be scaled, then I never will have that realistic combat build I've always wanted I guess...
There has to be a way to scale creature damage... if not in the stock CS, through scripts and OBSE as has been suggested. The Creature Damage Fix mod does indeed work for what it does but only deals with creature's using weapons. However, though I also don't know OB scripts, it seems like that mod could be a good basis for developing a script that would actually work to scale non-weapon creature damage as well. It's just quite frustrating that there isn't just a stock setting for scaling creature damage like there is for weapon damage...
There is no easy way to adjust creature damage with a simple game setting or something similar. Believe me, this was actually one of the first things I tried when I started modding (since I always hated the long lasting battles in Oblivion, but also wanted a balanced game) and after trying all kinds of different ways to achieve a result that would make combat more deadly in general for all kinds of damage PPP is
the way to go. I don't know of any other mods that scale all damage evenly for both the player and actors attacking the player no matter where it comes from. Spells, creatures, weapons, traps - doesn't matter.
Simply use the damage multiplier from PPP and get rid of the terribly unbalanced +200% damage for weapons (or whatever you are using). You can still use other mods to balance out damage proportions between various types of damage, like one of the numerous magic overhauls to make magic stronger compared to weapons/creatures or slightly increase weapon damage if you want weapons to be more powerful compared to creatures and/or magic.
The only thing that currently is not affected by PPP is the damage caused by non-player vs non-player actor. So fights between non-player actors will take longer than fights between PC and non-player actors, but they will be balanced so a legion soldier will not cut a Clannfear in half with two hits. There are a few new functions for OBSE that would allow to adjust this as well, but it's pretty complicated.
EDIT: fCreatureCalcDamage is for leveled creatures (creatures with a level offset) by the way. It works to adjust damage for them, but since many creatures (even more so with overhaul mods like FCOM etc) are not leveled it doesn't help much.