So with my previous assumption:
Ghoul (per OW):
+4: Fists; Athletics
+3: Endurance; Alertness; Intimidation; Presence
Powers:
Claws (weapon 2 fist attack)
Inhuman Strength & Speed
Supernatural Recovery
Pure Mortal (No stunts) (A)
+4: Weapons; Athletics
+3: Alertness; Endurance
Now if we assume all is equal (which will be everyone rolls 0) then Ghoul goes first. Generally you wont be in the same zone as an opponent at start. So ghoul moves toward mortal A and attacks. A takes hit the hit and is down a mild consequence with 2 stress, cant hit them back. A takes another hit next turn now has Mild, Moderate and 2 stress. Same next turn only now we have all but extreme and no stress. And so it goes on.
Now with the assumption that A had not used or gained any FP at this point. Ghoul goes first. FP to sustain the defense down to 7. Makes a maneuver to gain +2 on next turn. Ghoul again attacks and is blocked again from the use of yet another FP (6 left). A attacks and tags previous maneuver. Hits ghoul w/ +1 stress total 4 Ghoul now has 2 stress and a mild. Ghoul clears mild and attacks again (5). A attacks and uses FP to hit (4). Ghoul has 4 stress and Mild. Ghoul clears mild and attacks (3). A sets up maneuver. (2) and attacks Ghoul is at Moderate and 4 stress. (1) attack with FP (0) ghoul is at Moderate Severe no stress. Ghoul attacks 4 stress. set up maneuver to hit. Moderate and 4. Hits ghoul Mild Moderate Severe 2 stress. Moderate Severe and 2. Has to set up another maneuver. Mild Moderate Severe 4 stress. Hits Ghoul Mild Moderate Severe Extreme O stress. A is now at Mild Moderate Severe Extreme no stress and has to set up a maneuver to hit the ghoul. The ghoul will win next round and this is fight to the death.
Lets do it again. Ghoul rushes A and they use FP to block (7). A attacks and drops 7 fate points on personal aspects and scene aspect she has discovered before ghoul gets there. Total 17 Damage. Ghoul takes Mild Severe Extreme and one stress. Next ghoul gets rid of mild and inflicts 4 stress....
This can go on. In most of these situations the PM without stunts will lose. The only thing the stacked stunts do is bring them onto a similar level. A ghouls block is at 5 so there is a stunt to match that. A ghoul gets +2 to their damage so there is a stunt to match that. A ghoul probably should have taken something to increase its attack because now I have the slight advantage and can fare much better at this game.
I may have only spent 3 refresh where the ghoul spent 8 but...The ghoul can clear away 2 milds per scene. The ghoul gets bonuses to might and cant have endurance restrict. The ghoul can sneak better than I can. In all the powers, the ghoul is essenially getting the same stunt as me and two more stunts at minimum for 2 refresh, where the PM has to spend 3 or more refresh for those same stat boosts. The ghoul could use a weapon if it wanted and get a higher Weapon Rating but it should probably switch its +4 from fists to weapons. The ghoul could take a stunt that gives it +1 to attack but it does have that ability to clear out consequences so...
The stunt is balanced against the powers especially in regards to cost. Consider inhuman speed: Alertness at +4 for initiative, thats one stunt for the PM and the bonus is +2 not +4; All athletics checks at +1, there is another stunt; +2 to athletics when sprinting, well there is another we are up to 3; Ignore the -1 penalty when moving as part of another physical action, that makes 4; Difficulty factors when moving durring stealth are reduced by two, that makes five.
So for two refresh the ghoul gets 5 refresh worth of stunts, one of which is more powerful than normally allowed. A PM only gets a +2 refresh for being PM so with this one stunt the PM is already underpowered by one refresh. This goes on for each power that the ghoul has (save claws which is a guaranteed weapon as opposed to the one that can be lost and thats only a 1 refresh power anyway). These stunts arent overpowered, they just have the advantage of being able to combine themselves easier.