Okay, I played up until Chapter III on Normal and then I decided to restart the game and do Iorveth's path and kill the trolls etc., however, I changed the difficulty to Easy in order to fly through it and get back to Chapter III.

On Normal fist fighting went by very quickly, maybe a minute per fight, but now fist fights take 10 minutes each. It took me almost 45 minutes to beat the Fight Club mission in Chapter I. Is it supposed to be like this or am I mis-remembering how long fist fights last?

I noticed no change in the fistfighting in the EE edition, but to be fair - I never did a fistfight on Easy. Are the controls different on that difficulty level? Maybe you should try to change back to Normal, or Hard to get back to the way you were used to - just for that section.

10 minutes? That's way too long. I don't know that any fistfight has ever taken longer than a minute on any version. Did you try changing the difficulty back to normal to see if the fistfights still take that long?

I tried every single difficulty and turned the "Difficult QTEs" on and off. It made no difference.

I timed a fight by taking a potion with a 13 minute duration and by the end I had 2 minutes and change left.

The only different things I did to my previous save besides changing the difficulty to Easy were foregoing the tutorial mission and I killed Aryan. I'm 99% sure that Aryan had nothing to do with it though.

There's something strange for sure.

So, in the Fistfight, you are prompted to press W,A,S or D by the yellow letters on the screen - Top, Left, Bottom, Right - respectively. Assuming you press the correct letter in time, you will connect a blow to your opponent. It should only take 4-5 correct blows to down any opponent.

No potions needed.

Many find it easier to sit back a bit from the monitor with your eyes lazily on Geralt. You will see the yellow letters flash on the screen as described above, sometimes in combination.

Are you doing that?

I'm getting the feeling we may have a bit of a PEBCAK error here.

I'm doing everything correctly, I can get through the entire fight without missing a prompt and taking no damage, but it just lasts forever.

I started another new game a little while ago just to get to the first fist fight in the dungeon, except this time I did do the tutorial mission (chose Easy) and I spared Aryan like my first playthough, everything is normal again. I defeated the prison guard in two hits.

I wonder if it's the difficulty somehow not registering properly when not doing the tutorial mission, because I have a hard time believing that sparing Aryan makes a difference.

There is no diffuculty difference between levels,played on easy and dark both fights ends
about 20 seconds.

if anyone should be interested in a one hit fix solution:

go to your the witcher 2\CookedPC\abilities and edit geralt_basic.xml

Look for these lines:

#Damage group
<ff_damage_min mult="false" always_random="false" min="1" max="1"/>
<ff_damage_max mult="false" always_random="false" min="2" max="2"/>

and change them to

#Damage group
<ff_damage_min mult="false" always_random="false" min="1000" max="1000"/>
<ff_damage_max mult="false" always_random="false" min="2000" max="2000"/>